Microfabricated rubidium dielectric barrier discharge light sources for portable atomic clocks
ATOMIC CLOCKS: BASIC PRINCIPLES, APPLICATIONS AND …€¦ · Atomic clocks: basic principles,...
Transcript of ATOMIC CLOCKS: BASIC PRINCIPLES, APPLICATIONS AND …€¦ · Atomic clocks: basic principles,...
13th PSI Summer SchoolZug August 9-15 2014 1Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC CLOCKS BASIC PRINCIPLES APPLICATIONS AND CURRENT TRENDS
Gaetano Mileti Laboratoire Temps ndash Freacutequence (LTF) Universiteacute de Neuchacirctel
13th PSI Summer SchoolZug August 9-15 2014 2Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LABORATOIRE TEMPS ndash FREacuteQUENCE (LTF)
Time amp Frequency metrologyAtomic spectroscopyPrimary standardsOptical clocksCell standardsSpace clocks
Optical metrologyOptical combsXUV frequency combsStabilized lasersLaser characterisationLaser instruments
13th PSI Summer SchoolZug August 9-15 2014 3Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 4Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RECENT NOBEL PRIZES IN PHYSICS RELATED TO THE FIELD
2012 S Haroche D Wineland
Control of individual quantum objects Photons and atoms
2005 J Hall T Haensch R Glauber
Laser precision spectroscopy Optical comb Quantum optic
1997 S Chu C Cohen-Tannoudji W Philips
Laser manipulation of atoms
1989 N Ramsey W Paul H Dehmelt
Separated oscillatory fields method for atomic clocks
Ion trap techniques
And several others in the previous years (Kastler optical pumping etc)
13th PSI Summer SchoolZug August 9-15 2014 5Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 6Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Definition in SI system
The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of cesium 133 (1967)
Hzh
EEFrequency 7706311929120
AtomsQuartz oscillator
Reference for the user (5 MHz)
Interrogation
Feed-back
F=4
F=36 Sfrac12
This would be the frequency of an atomic clock in which the atomic transition is not perturbed and the stabilisation ldquoperfectrdquo
ATOMIC CLOCK FREQUENCY-STABILIZED OSCILLATOR
00
1
TPeriod
13th PSI Summer SchoolZug August 9-15 2014 7Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY DO WE NEED TO STABILIZE THE QUARTZ
Slide from JohnVig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
13th PSI Summer SchoolZug August 9-15 2014 8Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FIRST OVERVIEW OF APPLICATIONS AND NEEDS
Agriculture (seasons) ~ 1rsquo000rsquo000 s
Calendar (solstices equinoxes) ~ 100 rsquo000 s
Daily activities (professional social etc) ~ 1rsquo000 s
Determination of the longitude (sea navigation) ~ 1 s
Common electronic and telecommunication devices ~ 001 s
Advanced telecommunication devices ~ 0000rsquo001 s
Satellite navigation ~ 0000rsquo000rsquo001 s
Scientific research and primary metrology lt 0000rsquo000rsquo000rsquo1 s
Need of atomic clocks (in the device or to calibrate the device)
10-11
10-14
lt 10-14
13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Typically 5 or 10 MHz
9 192 631 770 Hz
Magnetic resonance
BLOC DIAGRAM OF AN ATOMIC CLOCK
Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator
bull Statistical and non-statistical analysis
Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
Systematic bias
Frequency of the oscillator
Statistical fluctuations
STABILITY AND ACCURACY
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
0
13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ALLAN DEVIATION
Frequency of the oscillator
1 )(1 K
K
t
tK dttyy generalindivergesyvarianceTrue ky22
212
12 )()( kky yy deviationAllany )(
bull Different types of noise processes affect differently the Allan deviation
bull Different applications require different (in)stabilities at given time scales
y() tells us how the
oscillator under test compares to an ideal one
over the timescale
13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Magnetic resonance allows ldquospin fliprdquo
Magnetic resonance is a frequency selective phenomenon
Sig
nal
Probing frequency
Linewidth 0
0
0
Q
21
)(20
NSQ
Iy
BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE
J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981
Allan deviation
0
RT1
0
R resonance laquodurationraquo
13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Discriminatorslope D
Detection noise
Frequency noise
The most important parameters for the clockperformances are
The resonancequality factor Q
The signal to noise ratio SN
RELEVANT PARAMETERS OF THE RESONANCE SIGNAL
13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
BLOCH VECTOR FORMALISM (SEMI-CLASSIC)
2E
1E
The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field
Microwave transitions optical transitions 2 pulses etc
Atom (or ensemble of atoms)
Interacting field (RF microwave optical)
Bloch vector (fictitious spin)
tie
12 EE
spopulationofdifferencequadratureindipoleatomic
phaseindipoleatomic
wvu
s
R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)
13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHAT HAPPENS IN AN ATOMIC CLOCK
Generalised magnetic resonance allows ldquospin flipsrdquo
It is a frequency selective phenomenon
In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator
In each type of clock it is realised on different species in various configurations and with different detection techniques
Sig
nal
Probing frequency
Linewidth
Or series of pulses such asThe Ramsey scheme (2)
13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS
- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations
- Put (or select) as many atoms as possible atoms in one(of the two) levels
- Perform the ldquomagnetic resonancerdquo (in one or more steps)
- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)
- Apply the necessary correction to the quartz oscillator
000
s
100
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 2Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LABORATOIRE TEMPS ndash FREacuteQUENCE (LTF)
Time amp Frequency metrologyAtomic spectroscopyPrimary standardsOptical clocksCell standardsSpace clocks
Optical metrologyOptical combsXUV frequency combsStabilized lasersLaser characterisationLaser instruments
13th PSI Summer SchoolZug August 9-15 2014 3Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 4Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RECENT NOBEL PRIZES IN PHYSICS RELATED TO THE FIELD
2012 S Haroche D Wineland
Control of individual quantum objects Photons and atoms
2005 J Hall T Haensch R Glauber
Laser precision spectroscopy Optical comb Quantum optic
1997 S Chu C Cohen-Tannoudji W Philips
Laser manipulation of atoms
1989 N Ramsey W Paul H Dehmelt
Separated oscillatory fields method for atomic clocks
Ion trap techniques
And several others in the previous years (Kastler optical pumping etc)
13th PSI Summer SchoolZug August 9-15 2014 5Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 6Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Definition in SI system
The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of cesium 133 (1967)
Hzh
EEFrequency 7706311929120
AtomsQuartz oscillator
Reference for the user (5 MHz)
Interrogation
Feed-back
F=4
F=36 Sfrac12
This would be the frequency of an atomic clock in which the atomic transition is not perturbed and the stabilisation ldquoperfectrdquo
ATOMIC CLOCK FREQUENCY-STABILIZED OSCILLATOR
00
1
TPeriod
13th PSI Summer SchoolZug August 9-15 2014 7Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY DO WE NEED TO STABILIZE THE QUARTZ
Slide from JohnVig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
13th PSI Summer SchoolZug August 9-15 2014 8Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FIRST OVERVIEW OF APPLICATIONS AND NEEDS
Agriculture (seasons) ~ 1rsquo000rsquo000 s
Calendar (solstices equinoxes) ~ 100 rsquo000 s
Daily activities (professional social etc) ~ 1rsquo000 s
Determination of the longitude (sea navigation) ~ 1 s
Common electronic and telecommunication devices ~ 001 s
Advanced telecommunication devices ~ 0000rsquo001 s
Satellite navigation ~ 0000rsquo000rsquo001 s
Scientific research and primary metrology lt 0000rsquo000rsquo000rsquo1 s
Need of atomic clocks (in the device or to calibrate the device)
10-11
10-14
lt 10-14
13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Typically 5 or 10 MHz
9 192 631 770 Hz
Magnetic resonance
BLOC DIAGRAM OF AN ATOMIC CLOCK
Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator
bull Statistical and non-statistical analysis
Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
Systematic bias
Frequency of the oscillator
Statistical fluctuations
STABILITY AND ACCURACY
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
0
13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ALLAN DEVIATION
Frequency of the oscillator
1 )(1 K
K
t
tK dttyy generalindivergesyvarianceTrue ky22
212
12 )()( kky yy deviationAllany )(
bull Different types of noise processes affect differently the Allan deviation
bull Different applications require different (in)stabilities at given time scales
y() tells us how the
oscillator under test compares to an ideal one
over the timescale
13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Magnetic resonance allows ldquospin fliprdquo
Magnetic resonance is a frequency selective phenomenon
Sig
nal
Probing frequency
Linewidth 0
0
0
Q
21
)(20
NSQ
Iy
BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE
J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981
Allan deviation
0
RT1
0
R resonance laquodurationraquo
13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Discriminatorslope D
Detection noise
Frequency noise
The most important parameters for the clockperformances are
The resonancequality factor Q
The signal to noise ratio SN
RELEVANT PARAMETERS OF THE RESONANCE SIGNAL
13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
BLOCH VECTOR FORMALISM (SEMI-CLASSIC)
2E
1E
The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field
Microwave transitions optical transitions 2 pulses etc
Atom (or ensemble of atoms)
Interacting field (RF microwave optical)
Bloch vector (fictitious spin)
tie
12 EE
spopulationofdifferencequadratureindipoleatomic
phaseindipoleatomic
wvu
s
R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)
13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHAT HAPPENS IN AN ATOMIC CLOCK
Generalised magnetic resonance allows ldquospin flipsrdquo
It is a frequency selective phenomenon
In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator
In each type of clock it is realised on different species in various configurations and with different detection techniques
Sig
nal
Probing frequency
Linewidth
Or series of pulses such asThe Ramsey scheme (2)
13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS
- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations
- Put (or select) as many atoms as possible atoms in one(of the two) levels
- Perform the ldquomagnetic resonancerdquo (in one or more steps)
- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)
- Apply the necessary correction to the quartz oscillator
000
s
100
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 3Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 4Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RECENT NOBEL PRIZES IN PHYSICS RELATED TO THE FIELD
2012 S Haroche D Wineland
Control of individual quantum objects Photons and atoms
2005 J Hall T Haensch R Glauber
Laser precision spectroscopy Optical comb Quantum optic
1997 S Chu C Cohen-Tannoudji W Philips
Laser manipulation of atoms
1989 N Ramsey W Paul H Dehmelt
Separated oscillatory fields method for atomic clocks
Ion trap techniques
And several others in the previous years (Kastler optical pumping etc)
13th PSI Summer SchoolZug August 9-15 2014 5Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 6Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Definition in SI system
The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of cesium 133 (1967)
Hzh
EEFrequency 7706311929120
AtomsQuartz oscillator
Reference for the user (5 MHz)
Interrogation
Feed-back
F=4
F=36 Sfrac12
This would be the frequency of an atomic clock in which the atomic transition is not perturbed and the stabilisation ldquoperfectrdquo
ATOMIC CLOCK FREQUENCY-STABILIZED OSCILLATOR
00
1
TPeriod
13th PSI Summer SchoolZug August 9-15 2014 7Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY DO WE NEED TO STABILIZE THE QUARTZ
Slide from JohnVig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
13th PSI Summer SchoolZug August 9-15 2014 8Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FIRST OVERVIEW OF APPLICATIONS AND NEEDS
Agriculture (seasons) ~ 1rsquo000rsquo000 s
Calendar (solstices equinoxes) ~ 100 rsquo000 s
Daily activities (professional social etc) ~ 1rsquo000 s
Determination of the longitude (sea navigation) ~ 1 s
Common electronic and telecommunication devices ~ 001 s
Advanced telecommunication devices ~ 0000rsquo001 s
Satellite navigation ~ 0000rsquo000rsquo001 s
Scientific research and primary metrology lt 0000rsquo000rsquo000rsquo1 s
Need of atomic clocks (in the device or to calibrate the device)
10-11
10-14
lt 10-14
13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Typically 5 or 10 MHz
9 192 631 770 Hz
Magnetic resonance
BLOC DIAGRAM OF AN ATOMIC CLOCK
Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator
bull Statistical and non-statistical analysis
Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
Systematic bias
Frequency of the oscillator
Statistical fluctuations
STABILITY AND ACCURACY
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
0
13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ALLAN DEVIATION
Frequency of the oscillator
1 )(1 K
K
t
tK dttyy generalindivergesyvarianceTrue ky22
212
12 )()( kky yy deviationAllany )(
bull Different types of noise processes affect differently the Allan deviation
bull Different applications require different (in)stabilities at given time scales
y() tells us how the
oscillator under test compares to an ideal one
over the timescale
13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Magnetic resonance allows ldquospin fliprdquo
Magnetic resonance is a frequency selective phenomenon
Sig
nal
Probing frequency
Linewidth 0
0
0
Q
21
)(20
NSQ
Iy
BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE
J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981
Allan deviation
0
RT1
0
R resonance laquodurationraquo
13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Discriminatorslope D
Detection noise
Frequency noise
The most important parameters for the clockperformances are
The resonancequality factor Q
The signal to noise ratio SN
RELEVANT PARAMETERS OF THE RESONANCE SIGNAL
13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
BLOCH VECTOR FORMALISM (SEMI-CLASSIC)
2E
1E
The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field
Microwave transitions optical transitions 2 pulses etc
Atom (or ensemble of atoms)
Interacting field (RF microwave optical)
Bloch vector (fictitious spin)
tie
12 EE
spopulationofdifferencequadratureindipoleatomic
phaseindipoleatomic
wvu
s
R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)
13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHAT HAPPENS IN AN ATOMIC CLOCK
Generalised magnetic resonance allows ldquospin flipsrdquo
It is a frequency selective phenomenon
In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator
In each type of clock it is realised on different species in various configurations and with different detection techniques
Sig
nal
Probing frequency
Linewidth
Or series of pulses such asThe Ramsey scheme (2)
13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS
- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations
- Put (or select) as many atoms as possible atoms in one(of the two) levels
- Perform the ldquomagnetic resonancerdquo (in one or more steps)
- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)
- Apply the necessary correction to the quartz oscillator
000
s
100
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 4Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RECENT NOBEL PRIZES IN PHYSICS RELATED TO THE FIELD
2012 S Haroche D Wineland
Control of individual quantum objects Photons and atoms
2005 J Hall T Haensch R Glauber
Laser precision spectroscopy Optical comb Quantum optic
1997 S Chu C Cohen-Tannoudji W Philips
Laser manipulation of atoms
1989 N Ramsey W Paul H Dehmelt
Separated oscillatory fields method for atomic clocks
Ion trap techniques
And several others in the previous years (Kastler optical pumping etc)
13th PSI Summer SchoolZug August 9-15 2014 5Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 6Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Definition in SI system
The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of cesium 133 (1967)
Hzh
EEFrequency 7706311929120
AtomsQuartz oscillator
Reference for the user (5 MHz)
Interrogation
Feed-back
F=4
F=36 Sfrac12
This would be the frequency of an atomic clock in which the atomic transition is not perturbed and the stabilisation ldquoperfectrdquo
ATOMIC CLOCK FREQUENCY-STABILIZED OSCILLATOR
00
1
TPeriod
13th PSI Summer SchoolZug August 9-15 2014 7Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY DO WE NEED TO STABILIZE THE QUARTZ
Slide from JohnVig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
13th PSI Summer SchoolZug August 9-15 2014 8Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FIRST OVERVIEW OF APPLICATIONS AND NEEDS
Agriculture (seasons) ~ 1rsquo000rsquo000 s
Calendar (solstices equinoxes) ~ 100 rsquo000 s
Daily activities (professional social etc) ~ 1rsquo000 s
Determination of the longitude (sea navigation) ~ 1 s
Common electronic and telecommunication devices ~ 001 s
Advanced telecommunication devices ~ 0000rsquo001 s
Satellite navigation ~ 0000rsquo000rsquo001 s
Scientific research and primary metrology lt 0000rsquo000rsquo000rsquo1 s
Need of atomic clocks (in the device or to calibrate the device)
10-11
10-14
lt 10-14
13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Typically 5 or 10 MHz
9 192 631 770 Hz
Magnetic resonance
BLOC DIAGRAM OF AN ATOMIC CLOCK
Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator
bull Statistical and non-statistical analysis
Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
Systematic bias
Frequency of the oscillator
Statistical fluctuations
STABILITY AND ACCURACY
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
0
13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ALLAN DEVIATION
Frequency of the oscillator
1 )(1 K
K
t
tK dttyy generalindivergesyvarianceTrue ky22
212
12 )()( kky yy deviationAllany )(
bull Different types of noise processes affect differently the Allan deviation
bull Different applications require different (in)stabilities at given time scales
y() tells us how the
oscillator under test compares to an ideal one
over the timescale
13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Magnetic resonance allows ldquospin fliprdquo
Magnetic resonance is a frequency selective phenomenon
Sig
nal
Probing frequency
Linewidth 0
0
0
Q
21
)(20
NSQ
Iy
BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE
J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981
Allan deviation
0
RT1
0
R resonance laquodurationraquo
13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Discriminatorslope D
Detection noise
Frequency noise
The most important parameters for the clockperformances are
The resonancequality factor Q
The signal to noise ratio SN
RELEVANT PARAMETERS OF THE RESONANCE SIGNAL
13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
BLOCH VECTOR FORMALISM (SEMI-CLASSIC)
2E
1E
The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field
Microwave transitions optical transitions 2 pulses etc
Atom (or ensemble of atoms)
Interacting field (RF microwave optical)
Bloch vector (fictitious spin)
tie
12 EE
spopulationofdifferencequadratureindipoleatomic
phaseindipoleatomic
wvu
s
R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)
13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHAT HAPPENS IN AN ATOMIC CLOCK
Generalised magnetic resonance allows ldquospin flipsrdquo
It is a frequency selective phenomenon
In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator
In each type of clock it is realised on different species in various configurations and with different detection techniques
Sig
nal
Probing frequency
Linewidth
Or series of pulses such asThe Ramsey scheme (2)
13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS
- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations
- Put (or select) as many atoms as possible atoms in one(of the two) levels
- Perform the ldquomagnetic resonancerdquo (in one or more steps)
- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)
- Apply the necessary correction to the quartz oscillator
000
s
100
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 5Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 6Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Definition in SI system
The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of cesium 133 (1967)
Hzh
EEFrequency 7706311929120
AtomsQuartz oscillator
Reference for the user (5 MHz)
Interrogation
Feed-back
F=4
F=36 Sfrac12
This would be the frequency of an atomic clock in which the atomic transition is not perturbed and the stabilisation ldquoperfectrdquo
ATOMIC CLOCK FREQUENCY-STABILIZED OSCILLATOR
00
1
TPeriod
13th PSI Summer SchoolZug August 9-15 2014 7Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY DO WE NEED TO STABILIZE THE QUARTZ
Slide from JohnVig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
13th PSI Summer SchoolZug August 9-15 2014 8Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FIRST OVERVIEW OF APPLICATIONS AND NEEDS
Agriculture (seasons) ~ 1rsquo000rsquo000 s
Calendar (solstices equinoxes) ~ 100 rsquo000 s
Daily activities (professional social etc) ~ 1rsquo000 s
Determination of the longitude (sea navigation) ~ 1 s
Common electronic and telecommunication devices ~ 001 s
Advanced telecommunication devices ~ 0000rsquo001 s
Satellite navigation ~ 0000rsquo000rsquo001 s
Scientific research and primary metrology lt 0000rsquo000rsquo000rsquo1 s
Need of atomic clocks (in the device or to calibrate the device)
10-11
10-14
lt 10-14
13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Typically 5 or 10 MHz
9 192 631 770 Hz
Magnetic resonance
BLOC DIAGRAM OF AN ATOMIC CLOCK
Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator
bull Statistical and non-statistical analysis
Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
Systematic bias
Frequency of the oscillator
Statistical fluctuations
STABILITY AND ACCURACY
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
0
13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ALLAN DEVIATION
Frequency of the oscillator
1 )(1 K
K
t
tK dttyy generalindivergesyvarianceTrue ky22
212
12 )()( kky yy deviationAllany )(
bull Different types of noise processes affect differently the Allan deviation
bull Different applications require different (in)stabilities at given time scales
y() tells us how the
oscillator under test compares to an ideal one
over the timescale
13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Magnetic resonance allows ldquospin fliprdquo
Magnetic resonance is a frequency selective phenomenon
Sig
nal
Probing frequency
Linewidth 0
0
0
Q
21
)(20
NSQ
Iy
BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE
J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981
Allan deviation
0
RT1
0
R resonance laquodurationraquo
13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Discriminatorslope D
Detection noise
Frequency noise
The most important parameters for the clockperformances are
The resonancequality factor Q
The signal to noise ratio SN
RELEVANT PARAMETERS OF THE RESONANCE SIGNAL
13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
BLOCH VECTOR FORMALISM (SEMI-CLASSIC)
2E
1E
The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field
Microwave transitions optical transitions 2 pulses etc
Atom (or ensemble of atoms)
Interacting field (RF microwave optical)
Bloch vector (fictitious spin)
tie
12 EE
spopulationofdifferencequadratureindipoleatomic
phaseindipoleatomic
wvu
s
R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)
13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHAT HAPPENS IN AN ATOMIC CLOCK
Generalised magnetic resonance allows ldquospin flipsrdquo
It is a frequency selective phenomenon
In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator
In each type of clock it is realised on different species in various configurations and with different detection techniques
Sig
nal
Probing frequency
Linewidth
Or series of pulses such asThe Ramsey scheme (2)
13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS
- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations
- Put (or select) as many atoms as possible atoms in one(of the two) levels
- Perform the ldquomagnetic resonancerdquo (in one or more steps)
- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)
- Apply the necessary correction to the quartz oscillator
000
s
100
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 6Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Definition in SI system
The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of cesium 133 (1967)
Hzh
EEFrequency 7706311929120
AtomsQuartz oscillator
Reference for the user (5 MHz)
Interrogation
Feed-back
F=4
F=36 Sfrac12
This would be the frequency of an atomic clock in which the atomic transition is not perturbed and the stabilisation ldquoperfectrdquo
ATOMIC CLOCK FREQUENCY-STABILIZED OSCILLATOR
00
1
TPeriod
13th PSI Summer SchoolZug August 9-15 2014 7Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY DO WE NEED TO STABILIZE THE QUARTZ
Slide from JohnVig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
13th PSI Summer SchoolZug August 9-15 2014 8Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FIRST OVERVIEW OF APPLICATIONS AND NEEDS
Agriculture (seasons) ~ 1rsquo000rsquo000 s
Calendar (solstices equinoxes) ~ 100 rsquo000 s
Daily activities (professional social etc) ~ 1rsquo000 s
Determination of the longitude (sea navigation) ~ 1 s
Common electronic and telecommunication devices ~ 001 s
Advanced telecommunication devices ~ 0000rsquo001 s
Satellite navigation ~ 0000rsquo000rsquo001 s
Scientific research and primary metrology lt 0000rsquo000rsquo000rsquo1 s
Need of atomic clocks (in the device or to calibrate the device)
10-11
10-14
lt 10-14
13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Typically 5 or 10 MHz
9 192 631 770 Hz
Magnetic resonance
BLOC DIAGRAM OF AN ATOMIC CLOCK
Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator
bull Statistical and non-statistical analysis
Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
Systematic bias
Frequency of the oscillator
Statistical fluctuations
STABILITY AND ACCURACY
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
0
13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ALLAN DEVIATION
Frequency of the oscillator
1 )(1 K
K
t
tK dttyy generalindivergesyvarianceTrue ky22
212
12 )()( kky yy deviationAllany )(
bull Different types of noise processes affect differently the Allan deviation
bull Different applications require different (in)stabilities at given time scales
y() tells us how the
oscillator under test compares to an ideal one
over the timescale
13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Magnetic resonance allows ldquospin fliprdquo
Magnetic resonance is a frequency selective phenomenon
Sig
nal
Probing frequency
Linewidth 0
0
0
Q
21
)(20
NSQ
Iy
BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE
J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981
Allan deviation
0
RT1
0
R resonance laquodurationraquo
13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Discriminatorslope D
Detection noise
Frequency noise
The most important parameters for the clockperformances are
The resonancequality factor Q
The signal to noise ratio SN
RELEVANT PARAMETERS OF THE RESONANCE SIGNAL
13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
BLOCH VECTOR FORMALISM (SEMI-CLASSIC)
2E
1E
The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field
Microwave transitions optical transitions 2 pulses etc
Atom (or ensemble of atoms)
Interacting field (RF microwave optical)
Bloch vector (fictitious spin)
tie
12 EE
spopulationofdifferencequadratureindipoleatomic
phaseindipoleatomic
wvu
s
R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)
13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHAT HAPPENS IN AN ATOMIC CLOCK
Generalised magnetic resonance allows ldquospin flipsrdquo
It is a frequency selective phenomenon
In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator
In each type of clock it is realised on different species in various configurations and with different detection techniques
Sig
nal
Probing frequency
Linewidth
Or series of pulses such asThe Ramsey scheme (2)
13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS
- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations
- Put (or select) as many atoms as possible atoms in one(of the two) levels
- Perform the ldquomagnetic resonancerdquo (in one or more steps)
- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)
- Apply the necessary correction to the quartz oscillator
000
s
100
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 7Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY DO WE NEED TO STABILIZE THE QUARTZ
Slide from JohnVig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
13th PSI Summer SchoolZug August 9-15 2014 8Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FIRST OVERVIEW OF APPLICATIONS AND NEEDS
Agriculture (seasons) ~ 1rsquo000rsquo000 s
Calendar (solstices equinoxes) ~ 100 rsquo000 s
Daily activities (professional social etc) ~ 1rsquo000 s
Determination of the longitude (sea navigation) ~ 1 s
Common electronic and telecommunication devices ~ 001 s
Advanced telecommunication devices ~ 0000rsquo001 s
Satellite navigation ~ 0000rsquo000rsquo001 s
Scientific research and primary metrology lt 0000rsquo000rsquo000rsquo1 s
Need of atomic clocks (in the device or to calibrate the device)
10-11
10-14
lt 10-14
13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Typically 5 or 10 MHz
9 192 631 770 Hz
Magnetic resonance
BLOC DIAGRAM OF AN ATOMIC CLOCK
Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator
bull Statistical and non-statistical analysis
Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
Systematic bias
Frequency of the oscillator
Statistical fluctuations
STABILITY AND ACCURACY
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
0
13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ALLAN DEVIATION
Frequency of the oscillator
1 )(1 K
K
t
tK dttyy generalindivergesyvarianceTrue ky22
212
12 )()( kky yy deviationAllany )(
bull Different types of noise processes affect differently the Allan deviation
bull Different applications require different (in)stabilities at given time scales
y() tells us how the
oscillator under test compares to an ideal one
over the timescale
13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Magnetic resonance allows ldquospin fliprdquo
Magnetic resonance is a frequency selective phenomenon
Sig
nal
Probing frequency
Linewidth 0
0
0
Q
21
)(20
NSQ
Iy
BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE
J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981
Allan deviation
0
RT1
0
R resonance laquodurationraquo
13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Discriminatorslope D
Detection noise
Frequency noise
The most important parameters for the clockperformances are
The resonancequality factor Q
The signal to noise ratio SN
RELEVANT PARAMETERS OF THE RESONANCE SIGNAL
13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
BLOCH VECTOR FORMALISM (SEMI-CLASSIC)
2E
1E
The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field
Microwave transitions optical transitions 2 pulses etc
Atom (or ensemble of atoms)
Interacting field (RF microwave optical)
Bloch vector (fictitious spin)
tie
12 EE
spopulationofdifferencequadratureindipoleatomic
phaseindipoleatomic
wvu
s
R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)
13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHAT HAPPENS IN AN ATOMIC CLOCK
Generalised magnetic resonance allows ldquospin flipsrdquo
It is a frequency selective phenomenon
In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator
In each type of clock it is realised on different species in various configurations and with different detection techniques
Sig
nal
Probing frequency
Linewidth
Or series of pulses such asThe Ramsey scheme (2)
13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS
- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations
- Put (or select) as many atoms as possible atoms in one(of the two) levels
- Perform the ldquomagnetic resonancerdquo (in one or more steps)
- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)
- Apply the necessary correction to the quartz oscillator
000
s
100
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 8Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FIRST OVERVIEW OF APPLICATIONS AND NEEDS
Agriculture (seasons) ~ 1rsquo000rsquo000 s
Calendar (solstices equinoxes) ~ 100 rsquo000 s
Daily activities (professional social etc) ~ 1rsquo000 s
Determination of the longitude (sea navigation) ~ 1 s
Common electronic and telecommunication devices ~ 001 s
Advanced telecommunication devices ~ 0000rsquo001 s
Satellite navigation ~ 0000rsquo000rsquo001 s
Scientific research and primary metrology lt 0000rsquo000rsquo000rsquo1 s
Need of atomic clocks (in the device or to calibrate the device)
10-11
10-14
lt 10-14
13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Typically 5 or 10 MHz
9 192 631 770 Hz
Magnetic resonance
BLOC DIAGRAM OF AN ATOMIC CLOCK
Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator
bull Statistical and non-statistical analysis
Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
Systematic bias
Frequency of the oscillator
Statistical fluctuations
STABILITY AND ACCURACY
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
0
13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ALLAN DEVIATION
Frequency of the oscillator
1 )(1 K
K
t
tK dttyy generalindivergesyvarianceTrue ky22
212
12 )()( kky yy deviationAllany )(
bull Different types of noise processes affect differently the Allan deviation
bull Different applications require different (in)stabilities at given time scales
y() tells us how the
oscillator under test compares to an ideal one
over the timescale
13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Magnetic resonance allows ldquospin fliprdquo
Magnetic resonance is a frequency selective phenomenon
Sig
nal
Probing frequency
Linewidth 0
0
0
Q
21
)(20
NSQ
Iy
BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE
J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981
Allan deviation
0
RT1
0
R resonance laquodurationraquo
13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Discriminatorslope D
Detection noise
Frequency noise
The most important parameters for the clockperformances are
The resonancequality factor Q
The signal to noise ratio SN
RELEVANT PARAMETERS OF THE RESONANCE SIGNAL
13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
BLOCH VECTOR FORMALISM (SEMI-CLASSIC)
2E
1E
The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field
Microwave transitions optical transitions 2 pulses etc
Atom (or ensemble of atoms)
Interacting field (RF microwave optical)
Bloch vector (fictitious spin)
tie
12 EE
spopulationofdifferencequadratureindipoleatomic
phaseindipoleatomic
wvu
s
R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)
13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHAT HAPPENS IN AN ATOMIC CLOCK
Generalised magnetic resonance allows ldquospin flipsrdquo
It is a frequency selective phenomenon
In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator
In each type of clock it is realised on different species in various configurations and with different detection techniques
Sig
nal
Probing frequency
Linewidth
Or series of pulses such asThe Ramsey scheme (2)
13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS
- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations
- Put (or select) as many atoms as possible atoms in one(of the two) levels
- Perform the ldquomagnetic resonancerdquo (in one or more steps)
- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)
- Apply the necessary correction to the quartz oscillator
000
s
100
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Typically 5 or 10 MHz
9 192 631 770 Hz
Magnetic resonance
BLOC DIAGRAM OF AN ATOMIC CLOCK
Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator
bull Statistical and non-statistical analysis
Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
Systematic bias
Frequency of the oscillator
Statistical fluctuations
STABILITY AND ACCURACY
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
0
13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ALLAN DEVIATION
Frequency of the oscillator
1 )(1 K
K
t
tK dttyy generalindivergesyvarianceTrue ky22
212
12 )()( kky yy deviationAllany )(
bull Different types of noise processes affect differently the Allan deviation
bull Different applications require different (in)stabilities at given time scales
y() tells us how the
oscillator under test compares to an ideal one
over the timescale
13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Magnetic resonance allows ldquospin fliprdquo
Magnetic resonance is a frequency selective phenomenon
Sig
nal
Probing frequency
Linewidth 0
0
0
Q
21
)(20
NSQ
Iy
BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE
J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981
Allan deviation
0
RT1
0
R resonance laquodurationraquo
13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Discriminatorslope D
Detection noise
Frequency noise
The most important parameters for the clockperformances are
The resonancequality factor Q
The signal to noise ratio SN
RELEVANT PARAMETERS OF THE RESONANCE SIGNAL
13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
BLOCH VECTOR FORMALISM (SEMI-CLASSIC)
2E
1E
The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field
Microwave transitions optical transitions 2 pulses etc
Atom (or ensemble of atoms)
Interacting field (RF microwave optical)
Bloch vector (fictitious spin)
tie
12 EE
spopulationofdifferencequadratureindipoleatomic
phaseindipoleatomic
wvu
s
R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)
13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHAT HAPPENS IN AN ATOMIC CLOCK
Generalised magnetic resonance allows ldquospin flipsrdquo
It is a frequency selective phenomenon
In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator
In each type of clock it is realised on different species in various configurations and with different detection techniques
Sig
nal
Probing frequency
Linewidth
Or series of pulses such asThe Ramsey scheme (2)
13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS
- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations
- Put (or select) as many atoms as possible atoms in one(of the two) levels
- Perform the ldquomagnetic resonancerdquo (in one or more steps)
- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)
- Apply the necessary correction to the quartz oscillator
000
s
100
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator
bull Statistical and non-statistical analysis
Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo
Systematic bias
Frequency of the oscillator
Statistical fluctuations
STABILITY AND ACCURACY
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
Stable but not accurate
Not stable and not accurate
Not stable but (relatively) accurate
Stable and accurate
0
13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ALLAN DEVIATION
Frequency of the oscillator
1 )(1 K
K
t
tK dttyy generalindivergesyvarianceTrue ky22
212
12 )()( kky yy deviationAllany )(
bull Different types of noise processes affect differently the Allan deviation
bull Different applications require different (in)stabilities at given time scales
y() tells us how the
oscillator under test compares to an ideal one
over the timescale
13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Magnetic resonance allows ldquospin fliprdquo
Magnetic resonance is a frequency selective phenomenon
Sig
nal
Probing frequency
Linewidth 0
0
0
Q
21
)(20
NSQ
Iy
BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE
J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981
Allan deviation
0
RT1
0
R resonance laquodurationraquo
13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Discriminatorslope D
Detection noise
Frequency noise
The most important parameters for the clockperformances are
The resonancequality factor Q
The signal to noise ratio SN
RELEVANT PARAMETERS OF THE RESONANCE SIGNAL
13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
BLOCH VECTOR FORMALISM (SEMI-CLASSIC)
2E
1E
The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field
Microwave transitions optical transitions 2 pulses etc
Atom (or ensemble of atoms)
Interacting field (RF microwave optical)
Bloch vector (fictitious spin)
tie
12 EE
spopulationofdifferencequadratureindipoleatomic
phaseindipoleatomic
wvu
s
R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)
13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHAT HAPPENS IN AN ATOMIC CLOCK
Generalised magnetic resonance allows ldquospin flipsrdquo
It is a frequency selective phenomenon
In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator
In each type of clock it is realised on different species in various configurations and with different detection techniques
Sig
nal
Probing frequency
Linewidth
Or series of pulses such asThe Ramsey scheme (2)
13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS
- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations
- Put (or select) as many atoms as possible atoms in one(of the two) levels
- Perform the ldquomagnetic resonancerdquo (in one or more steps)
- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)
- Apply the necessary correction to the quartz oscillator
000
s
100
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ALLAN DEVIATION
Frequency of the oscillator
1 )(1 K
K
t
tK dttyy generalindivergesyvarianceTrue ky22
212
12 )()( kky yy deviationAllany )(
bull Different types of noise processes affect differently the Allan deviation
bull Different applications require different (in)stabilities at given time scales
y() tells us how the
oscillator under test compares to an ideal one
over the timescale
13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Magnetic resonance allows ldquospin fliprdquo
Magnetic resonance is a frequency selective phenomenon
Sig
nal
Probing frequency
Linewidth 0
0
0
Q
21
)(20
NSQ
Iy
BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE
J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981
Allan deviation
0
RT1
0
R resonance laquodurationraquo
13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Discriminatorslope D
Detection noise
Frequency noise
The most important parameters for the clockperformances are
The resonancequality factor Q
The signal to noise ratio SN
RELEVANT PARAMETERS OF THE RESONANCE SIGNAL
13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
BLOCH VECTOR FORMALISM (SEMI-CLASSIC)
2E
1E
The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field
Microwave transitions optical transitions 2 pulses etc
Atom (or ensemble of atoms)
Interacting field (RF microwave optical)
Bloch vector (fictitious spin)
tie
12 EE
spopulationofdifferencequadratureindipoleatomic
phaseindipoleatomic
wvu
s
R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)
13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHAT HAPPENS IN AN ATOMIC CLOCK
Generalised magnetic resonance allows ldquospin flipsrdquo
It is a frequency selective phenomenon
In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator
In each type of clock it is realised on different species in various configurations and with different detection techniques
Sig
nal
Probing frequency
Linewidth
Or series of pulses such asThe Ramsey scheme (2)
13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS
- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations
- Put (or select) as many atoms as possible atoms in one(of the two) levels
- Perform the ldquomagnetic resonancerdquo (in one or more steps)
- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)
- Apply the necessary correction to the quartz oscillator
000
s
100
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Magnetic resonance allows ldquospin fliprdquo
Magnetic resonance is a frequency selective phenomenon
Sig
nal
Probing frequency
Linewidth 0
0
0
Q
21
)(20
NSQ
Iy
BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE
J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981
Allan deviation
0
RT1
0
R resonance laquodurationraquo
13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Discriminatorslope D
Detection noise
Frequency noise
The most important parameters for the clockperformances are
The resonancequality factor Q
The signal to noise ratio SN
RELEVANT PARAMETERS OF THE RESONANCE SIGNAL
13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
BLOCH VECTOR FORMALISM (SEMI-CLASSIC)
2E
1E
The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field
Microwave transitions optical transitions 2 pulses etc
Atom (or ensemble of atoms)
Interacting field (RF microwave optical)
Bloch vector (fictitious spin)
tie
12 EE
spopulationofdifferencequadratureindipoleatomic
phaseindipoleatomic
wvu
s
R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)
13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHAT HAPPENS IN AN ATOMIC CLOCK
Generalised magnetic resonance allows ldquospin flipsrdquo
It is a frequency selective phenomenon
In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator
In each type of clock it is realised on different species in various configurations and with different detection techniques
Sig
nal
Probing frequency
Linewidth
Or series of pulses such asThe Ramsey scheme (2)
13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS
- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations
- Put (or select) as many atoms as possible atoms in one(of the two) levels
- Perform the ldquomagnetic resonancerdquo (in one or more steps)
- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)
- Apply the necessary correction to the quartz oscillator
000
s
100
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Discriminatorslope D
Detection noise
Frequency noise
The most important parameters for the clockperformances are
The resonancequality factor Q
The signal to noise ratio SN
RELEVANT PARAMETERS OF THE RESONANCE SIGNAL
13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
BLOCH VECTOR FORMALISM (SEMI-CLASSIC)
2E
1E
The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field
Microwave transitions optical transitions 2 pulses etc
Atom (or ensemble of atoms)
Interacting field (RF microwave optical)
Bloch vector (fictitious spin)
tie
12 EE
spopulationofdifferencequadratureindipoleatomic
phaseindipoleatomic
wvu
s
R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)
13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHAT HAPPENS IN AN ATOMIC CLOCK
Generalised magnetic resonance allows ldquospin flipsrdquo
It is a frequency selective phenomenon
In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator
In each type of clock it is realised on different species in various configurations and with different detection techniques
Sig
nal
Probing frequency
Linewidth
Or series of pulses such asThe Ramsey scheme (2)
13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS
- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations
- Put (or select) as many atoms as possible atoms in one(of the two) levels
- Perform the ldquomagnetic resonancerdquo (in one or more steps)
- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)
- Apply the necessary correction to the quartz oscillator
000
s
100
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
BLOCH VECTOR FORMALISM (SEMI-CLASSIC)
2E
1E
The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field
Microwave transitions optical transitions 2 pulses etc
Atom (or ensemble of atoms)
Interacting field (RF microwave optical)
Bloch vector (fictitious spin)
tie
12 EE
spopulationofdifferencequadratureindipoleatomic
phaseindipoleatomic
wvu
s
R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)
13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHAT HAPPENS IN AN ATOMIC CLOCK
Generalised magnetic resonance allows ldquospin flipsrdquo
It is a frequency selective phenomenon
In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator
In each type of clock it is realised on different species in various configurations and with different detection techniques
Sig
nal
Probing frequency
Linewidth
Or series of pulses such asThe Ramsey scheme (2)
13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS
- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations
- Put (or select) as many atoms as possible atoms in one(of the two) levels
- Perform the ldquomagnetic resonancerdquo (in one or more steps)
- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)
- Apply the necessary correction to the quartz oscillator
000
s
100
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHAT HAPPENS IN AN ATOMIC CLOCK
Generalised magnetic resonance allows ldquospin flipsrdquo
It is a frequency selective phenomenon
In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator
In each type of clock it is realised on different species in various configurations and with different detection techniques
Sig
nal
Probing frequency
Linewidth
Or series of pulses such asThe Ramsey scheme (2)
13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS
- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations
- Put (or select) as many atoms as possible atoms in one(of the two) levels
- Perform the ldquomagnetic resonancerdquo (in one or more steps)
- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)
- Apply the necessary correction to the quartz oscillator
000
s
100
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS
- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations
- Put (or select) as many atoms as possible atoms in one(of the two) levels
- Perform the ldquomagnetic resonancerdquo (in one or more steps)
- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)
- Apply the necessary correction to the quartz oscillator
000
s
100
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC BEAM FREQUENCY STANDARDS
Stern-Gerlach (State selection) and Ramsey interrogation
000
s
0)cos()sin(
0
0
tt
100
010
100
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Primary (Cs) ndash Secondary
bull Passive ndash Active (H-Maser)
bull Commercial (Rb Cs H)
bull Ground or Space applications
bull Laboratory ndash ldquoIn developmentrdquo
bull Microwave ndash Optical
bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip
CATEGORIES OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Radioastronomy Geodesy
(VLBI Radioastron etc)
Scientific Research Instrumentation
(Microgravity ACES HYPER etc)
Navigation amp Positioning
(Galileo GPS GLONASS etc)
Telecommunications
(Networks synchronisation etc)
Power distribution networks
(Smart power grids)
Metrology Time scales
(Primary and secondary standards H-Masers)
MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
CESIUM BEAM STANDARD
10-11 1s but accurate and very stable in the long term
Rabi pedestal
Ramsey fringe
RTLinewidth 1
0
atomsofspeedcavityofLengthLTR
v
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )
For a monokinetic beam
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
LASER-PUMPED BEAM STANDARDS
Optical pumping
1st Rabi(2) pulse
Free precession
2nd Rabi(2) pulse
Detection
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
)](cos[)( 0 rtEecirctrE L
forcepressureradiationoredissipativ
stab
forcedipolarorreactive
stab rrEvdecircrEudecircF )()()( 00
~ light-shift ~ absorption
Optical molassesOptical trapping (lattice tweezers etc)
Motivations reduce the Doppler effect increase interaction time etcRT
10
LASER RADIATIVE FORCES
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
COLD ATOMIC BEAM CLOCKS (FOUNTAINS)
-100 -50 0 50 10000
01
02
03
04
010101 142506
Lock
-in s
igna
l
M icrowave frequency detuning
Thermal beam v = 100 ms TR = 5 ms = 100 Hz
Cold fountain v = 4 ms TR = 05 s = 1 Hz
Next step microgravity (TR = 10 s = 01 Hz)
RTLinewidth 1 0
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
PRIMARY FREQUENCY STANDARDS
Systematic bias
Frequency
Statistical fluctuations
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)
Leap second
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RUBIDIUM VAPOUR CELL STANDARD
xmicrowaveresonatoramp source
vapourcell
Discharge lamp
QuartzLO
S
P
Double resonance
light
-wave
Tran
smitt
ed li
ght
Microwave frequency
kHz
10-11 1s10-13 10rsquo000s
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Rb87 LampRb85 filtre
Rb87 resonance cell
deacutetector
Microwave cavity
5304x106 5306x106 5308x106 5310x106 5312x1060108
0112
0116
0120
0124
0128
Tra
nsm
itted
ligh
t [V
on
10k
]
684 GHz - Synthesiser frequency [Hz]
S
P
Double resonance
light
-wave
DOUBLE RESONANCE (WITH A DISCHARGE LAMP)
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)
Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
HYDROGEN MASER
100 kg
() 1
10-13
1s
10-15
100s
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
VLBI (VERY LONG BASE INTERFEROMETRY)
H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution
Angular resolution ~ Diameter
1 radio-telescope ~ 1 mrad (10-3 rad)
2 radio-telescopes ~ 1 nrad (10-9 rad)
Earth rotation 1 mrad rarr 6 km rarr 14 s
cB sin
B
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space
RADIOASTRON MISSION (SPACE VLBI)
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
FUNDAMENTAL PHYSICS IN SPACE
Atomic Clock Ensemble in Space
Micro-gravity
Relativity
0
11Q
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Application GALILEO
1ns (10-14) time error
darr30 cm position error
Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)
darr10-12 1 s
18 kg 28 L 710-13 1 s
SPACE PASSIVE HYDROGEN MASER FOR GNSS
GNSS Global Navigation Satellite System
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)
In space Rubidium passive Hydrogen Maser (1deg generation)
On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)
GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)
2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
WHY RB CLOCK AND PASSIVE H MASER ON GALILEO
10-16
10-15
10-14
10-13
10-12
10-11
10-10
1 10 100 1000 104 105 106 107
Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold
Time interval (s)
Alla
n de
vFor 30 cm accuracy
Maximal Time error
1 nanosecond for
1s lt lt 20rsquo000 s
1410)00020( sy
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OUTLINE OF THE TALK
1) Introduction to atomic frequency standards
Basic (functional and physical) principles
Examples and applications of frequency standards
2) Current trends in the field
Optical frequency standards
Chip-scale atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RTQ
0
11
OPTICAL FREQUENCY STANDARDS
01010 rarr1015 Hz
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
MICROWAVE AND OPTICAL CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
EXAMPLE OF MORE RECENT ACHIEVEMENTS
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR
R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER COMPACT AND MINIATURE STABILISED LASERS
F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)
R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
RAMSEY INTERROGATION IN A CELL STANDARD
ν-ν0(Hz)Pr
obab
ility
pTRamsey
T1T1
Time-domain Ramsey scheme
bull Optical pumping( TP)bull Microwave pulse interrogation
(T1 TRamsey) bull Optical Detection (Td)
Rb vapor cell
Advantages Compactness Narrow linewidth Negligible light shift
Td
Det
Tp
tπ2 pulse
π2 pulse
S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Bring atomic timing precision to the size and power range previously covered by quartz oscillators
PrimaryStandard
CommercialBeam Clock
CompactAtomic Clock
WristwatchQuartz
Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3
Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1
PrecisionQuartz
Decreasing performance and sizepowercost
MiniatureAtomic Clock
New clocks
10‐101sday 10 cm3
120mW$300
MINIATURE ATOMIC CLOCKS
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
Dia=5 mm
L =10x10 mm 200 - 500 um
500-2000 um
Silicon wafer
Photolithography and cavity etching by DRIE
Wafer-level anodic bonding of Si with glass
Dicing
Cell closing Anodic bonding of glass lid
200 - 500 um
Rb deposition
NEUCHAcircTEL ANODIC BONDING TECHNOLOGY
IMT-SAMLAB
J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
SPECIAL MINIATURE CELLSIMT-SAMLAB
4-mm size Rb cellsMicro-fabrication technology for precise
control of cell geometryMulti-stack anodic bonding Thick glass core wafer
2 Si layers + 2 glass windows 4 steps of anodic bonding
Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings
Working alkali cells
5mm
R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)
Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Miniature cesium atomic clock
CPT (Coherent population trapping) technique
Applications
Telecom (4G LTE base stations)
Smart grid (power distribution)
Product specifications
Superior frequency and time stability 1 microsday
Compact size 51x51x18 mm3
Low power 2W
Lower price 400 CHF
Cs cell + Ne
4 Cs cell + Ne
Filter Photo-diode
Magnetic shield + coil
Pre-amplifier
Current source
RF generator= hf2
Quartz oscillator
High pass filter
Low pass filter
User 20 MHz
Laser
Clock implementation
51 mm
51 mm
15 mm
Prototype picture
QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)
Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
OTHER RECENT DEVELOPMENTS
Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)
Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)
Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)
Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)
the precision of atomic clocks is being improved down to 10-16 and beyond
bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements
bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space
bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)
bull Micro-fabrication techniques are crucial for extreme miniaturization
bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain
RTstabilityIn
00
0 1)(
TR cooling0 going optical
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989
bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)
bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005
bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005
Time amp Frequency conferences proceedings (including tutorials)
wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)
European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)
NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)
CUSO doctoral school on atomic clocks (2010 2012 amp 2014)
ESSENTIAL BIBLIOGRAPHY
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
Tower clocks (1300)verge-and-foliot mechanism
Precision Stabilityin seconds
per day
1 ns
1 s
100 ps
10 s
1000 s
Huygens Pendulum (1650)pendulum
Marine chronometers
(1750) Harrison
1 ms
Atomic clocks (1950)
Hydrogen Maser
Caesium beam Rubidium clock
Quartz oscillators
(1930)
1 s
Earth rotation
10 ns
10 ps
The metamorphosis oftime measurement
-3000 -1500 -170 800 1300 1600 19001700 2000
Marine chronometers Space atomic clocks
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf
13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends
Gaetano Mileti UniNe 10082014
THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland
Gaetanomiletiuninechwwwuninechltf