Post on 06-Oct-2020
1
Integrity Service Excellence
Ultrashort Pulse (USP) Laser – Matter
Interactions
5 MAR 2013
Dr. Riq Parra
Program Officer
AFOSR/RTB
Air Force Research Laboratory
DISTRIBUTION A: Approved for public release; distribution is unlimited
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1. REPORT DATE 05 MAR 2013 2. REPORT TYPE
3. DATES COVERED 00-00-2013 to 00-00-2013
4. TITLE AND SUBTITLE Ultrashort Pulse (USP) Laser-Matter Interactions
5a. CONTRACT NUMBER
5b. GRANT NUMBER
5c. PROGRAM ELEMENT NUMBER
6. AUTHOR(S) 5d. PROJECT NUMBER
5e. TASK NUMBER
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7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Air Force Office of Scientific Research ,AFOSR/RTB,875 N. Randolph,Arlington,VA,22203
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12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution unlimited
13. SUPPLEMENTARY NOTES Presented at the AFOSR Spring Review 2013, 4-8 March, Arlington, VA.
14. ABSTRACT
15. SUBJECT TERMS
16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as
Report (SAR)
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45
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Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18
2
500 700 900
nm
25 nm
300 nm
0.002 nm
BANDWITH
Modelocked femtosecond lasers
Light Emitting Diode
Ti:Sapphire modelocked fs laser
Sunlight
He-Ne cw laser
Wik
iped
ia
Wik
iped
ia
DISTRIBUTION A: Approved for public release; distribution is unlimited
time
time
time
time
Pulses!
3
2013 AFOSR SPRING REVIEW 3001O PORTFOLIO OVERVIEW
• The program aims to understand and control light sources exhibiting extreme bandwidth, peak power and temporal characteristics.
• Portfolio sub-areas: optical frequency combs, high-field science, attosecond physics.
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4
Applications of USP Lasers
USP Lasers
Secondary Radiation Sources generation of particle & photons • High power THz generation • Extreme ultraviolet
lithography • Biological soft x-ray
microscopy • Non-destructive evaluation • Medical imaging/therapy
Metrology stabilized, ultra-wide bandwidth • Ultra-stable freq sources • Optical waveform synthesis • High precision spectroscopy • Frequency/time transfer • High-capacity comms • Coherent LIDAR • Optical clocks • Calibration
Material Science ultrashort, high peak power • Surgery • Chemical analysis (LIBS) • Surface property
modification • Non-equilibrium ablation • Micromachining • Ultrafast photochemistry • Attochemistry
Propagation in media self-channeling • Remote sensing • Remote tagging • Directed energy • Electronic warfare • Countermeasures • Advanced sonar
Particle Acceleration ultrahigh electric field gradients • Table-top GeV electron
accelerators • MeV ion sources for
imaging • Isotope production • Hadron tumor therapy • Proton-based fast
ignition
DISTRIBUTION A: Approved for public release; distribution is unlimited
5
Outline
– Microresonator-based optical frequency combs
– High peak power, ultrashort pulse laser processing of materials
– Extreme ultraviolet (EUV) comb spectroscopy
– High harmonic interferometry
– Relativistic optics
DISTRIBUTION A: Approved for public release; distribution is unlimited Photo credits: DOI: 10.1038/nature05524, www.attoworld.de, E. Chowdhury (OSU)
6
Outline
– Microresonator-based optical frequency combs
– High peak power, ultrashort pulse laser processing of materials
– Extreme ultraviolet (EUV) comb spectroscopy
– High harmonic interferometry
– Relativistic optics
DISTRIBUTION A: Approved for public release; distribution is unlimited Photo credits: DOI: 10.1038/nature05524, www.attoworld.de, E. Chowdhury (OSU)
7
Optical frequency combs: Frequency & time domains
Source: Kippenberg et al., Science (2011); Diddams. DISTRIBUTION A: Approved for public release; distribution is unlimited
2∆φ
τr.t = 1/fr
t
E(t) ∆φ
Frequency domain
Time domain
8
Metrological applications of optical frequency combs
Source: Newbury, Nature Photonics (2011) DISTRIBUTION A: Approved for public release; distribution is unlimited AFR~I
9
Sou
rce:
Bra
je, P
hysi
cs 3
, 75
(201
0)
Combs in monolithic microresonators
High-Q mm crystalline resonators
top left doi: 10.1038/nphoton.2012.127 right doi: 10.1103/physreva.84.053833 bottom left doi: 10.1103/physrevlett.101.093902
CaF
2
Fused-quartz
MgF
2
Silica toroids
doi:1
0.10
38/n
atur
e064
01
Silicon nitride microrings
doi: 10.1038/nphoton.2009.259
DISTRIBUTION A: Approved for public release; distribution is unlimited
Parametric
Source: Kippenberg et al., Science (2011)
Conventional
10
Octave spanning bandwidths
Source: Del’Haye, Phys. Rev. Lett. 107, 063901 (2011), Okawachi, Opt. Lett. 36, 3398 (2011) DISTRIBUTION A: Approved for public release; distribution is unlimited
250
1200
20 2300
e o m "0 ';::" -20 Cl,)
3: ~ -40
200
1300 1400 1500
2000 1750
140 160 180
Frequency [THz] 150 125
1600 1700 1800 1900 2000 2100 2200 2300 2400
Wavelength [nm]
Wavelength (nm) 1550 1350 1200 1100 1000
++ 850 GHz 160 THz
200 220 240 260 280 300 Frequency (THz)
AFR~I
11
Why microresonators?
Source: Kippenberg et al., Science (2011) DISTRIBUTION A: Approved for public release; distribution is unlimited
Astronomy Spectroscopy
~ I Il l
1
-s <l -..c ~ 0.1 -~ "'0 c co .0
co c :2 0.01 (.) co '-LL
Waveform generation
~~IC:iJl
Optical clocks Telecommunication A1, A2, ... , AN
• ... • • :e
... : Nonlinear
?~?.~?.~~!~~ ....... ; .. . . . . .
... Si02
toroid
• Si02 sphere
• 1 E-3 ~~0.~1~~~~~1--~~~~10--~~~~1~00--~~~1~00-0~ HNLF
Mode spacing (GHz)
AFR~I
12
Comb generation dynamics
DISTRIBUTION A: Approved for public release; distribution is unlimited Graphics adapted from Herr, arXiv:1111.3071v1, 2011
Step 1 gain below threshold
Optical Spectrum
pump wP loss
w
AFR~I
13
Comb generation dynamics
DISTRIBUTION A: Approved for public release; distribution is unlimited Graphics adapted from Herr, arXiv:1111.3071v1, 2011
Step 2 multiple spacmg
w
AFR~I
14
Comb generation dynamics
DISTRIBUTION A: Approved for public release; distribution is unlimited Graphics adapted from Herr, arXiv:1111.3071v1, 2011
Step 3 cascading
w
AFR~I
15
Comb generation dynamics
DISTRIBUTION A: Approved for public release; distribution is unlimited Graphics adapted from Herr, arXiv:1111.3071v1, 2011
Step 4a native
spac1ng
w
AFR~I
16
Comb generation dynamics
DISTRIBUTION A: Approved for public release; distribution is unlimited Graphics adapted from Herr, arXiv:1111.3071v1, 2011
Step 4b native
spac1ng
AFR~I
17
Comb generation dynamics
DISTRIBUTION A: Approved for public release; distribution is unlimited Graphics adapted from Herr, arXiv:1111.3071v1, 2011
Step 5 sub-combs
• • • • • • • • • • • • •
AFR~I
18
Comb generation dynamics
DISTRIBUTION A: Approved for public release; distribution is unlimited Graphics adapted from Herr, arXiv:1111.3071v1, 2011
Step 6 mergmg
o-s:.+s:. ',, ',J
AFR~I
19
(FY12 BRI) Microresonator-based optical frequency combs
• Initiative aimed at exploring the fundamental physics of microresonator comb generation.
• Six efforts exploring:
– Spatio-temporal field mapping and control
– Silicon-carbide microdisks
– Silicon nitride resonators
– Mid-IR microresonators
– Time domain characterization
– Dispersion tailoring via slotted waveguides
DISTRIBUTION A: Approved for public release; distribution is unlimited
20
Temporal and Spectral Comb Generation Dynamics
Optical spectrum
RF spectrum Temporal output
Source: http://arxiv.org/abs/1211.1096v3
PI: Alex Gaeta, Cornell
DISTRIBUTION A: Approved for public release; distribution is unlimited
21
Temporal and Spectral Comb Generation Dynamics
Source: http://arxiv.org/abs/1211.1096v3
PI: Alex Gaeta, Cornell Optical spectrum
RF spectrum Temporal output
DISTRIBUTION A: Approved for public release; distribution is unlimited
22
Temporal and Spectral Comb Generation Dynamics
Transition to modelocking? Source: http://arxiv.org/abs/1211.1096v3
PI: Alex Gaeta, Cornell Optical spectrum
RF spectrum Temporal output
DISTRIBUTION A: Approved for public release; distribution is unlimited
23
99-GHz repetition rate
160-fs pulses
Ultrashort Pulses at 99 GHz
Source: http://arxiv.org/abs/1211.1096v3
PI: Alex Gaeta, Cornell
DISTRIBUTION A: Approved for public release; distribution is unlimited
24
Outline
– Microresonator-based optical frequency combs
– High peak power, ultrashort pulse laser processing of materials
– Extreme ultraviolet (EUV) comb spectroscopy
– High harmonic interferometry
– Relativistic optics
DISTRIBUTION A: Approved for public release; distribution is unlimited Photo credits: DOI: 10.1038/nature05524, www.attoworld.de, E. Chowdhury (OSU)
25
Long laser pulse Ultrashort pulses
Long laser pulse damages adjacent structures Ultrashort pulses no collateral damage
Source: C. Momma, A. Tunnermann et al., Opt. Commun. 129, 134 (1996) DISTRIBUTION A: Approved for public release; distribution is unlimited
26
Timescales of electron and lattice processes in laser-excited solids
Time-dependent processes in materials
Source: Sundaram, Nat Mater 1, 217 (2002), Mao, Applied Physics A 79, 1695 (2004).
10 – 100 fs
Multi- photon
Tunneling
Avalanche
Excitation mechanisms
DISTRIBUTION A: Approved for public release; distribution is unlimited
27
High peak power, ultrashort pulse laser processing of materials
• Ultrashort laser pulses open up novel possibilities and mechanisms for laser-solid interactions.
• Demonstrated femtosecond laser processing and surface texturing techniques to engineer surface structures & properties (e.g. darkened & colorized metals, hydrophilic & hydrophobic surfaces).
Colorized metals
PI: Chunlei Guo, U of Rochester
Hydrophilic Hydrophobic
DISTRIBUTION A: Approved for public release; distribution is unlimited
28
(FY13 BRI) High peak power, ultrashort pulse laser processing of materials
• Initiative aimed at developing a fundamental understanding of intense field laser ablation/damage in the femtosecond regime.
• Three multi-PI efforts exploring: – Dynamics of ionization – Fundamental dynamics of laser ablation – Defect states in multi-pulse interaction – Effect of structures on laser damage – First principle-based models, non-
adiabatic quantum MD, classical MD – Vary λ = 400 nm – 4 µm, τ = 5 – 1000 fs – Complex beam shapes (Bessel, Airy,
vortex, SSTF beams) – Novel laser-matter interaction geometries
(confined microexplosions, SSTF excitation, few-cycle pulses)
SSTF focus
Gratings
Classical MD
DISTRIBUTION A: Approved for public release; distribution is unlimited
29
Outline
– Microresonator-based optical frequency combs
– High peak power, ultrashort pulse laser processing of materials
– Extreme ultraviolet (EUV) comb spectroscopy
– High harmonic interferometry
– Relativistic optics
DISTRIBUTION A: Approved for public release; distribution is unlimited Photo credits: DOI: 10.1038/nature05524, www.attoworld.de, E. Chowdhury (OSU)
30
High Harmonic Generation (HHG)
Microscopic single-atom physics of HHG
Macroscopic phase-matched harmonic emission
Source: Popmintchev, Nat Photonics 4, 822 (2010), Popmintchev, Science 336, 1287 (2012) DISTRIBUTION A: Approved for public release; distribution is unlimited
2D electron wavepacket quantum simulation
Source: Luis Plaja, U Salamanca
31
Direct Frequency Comb Spectroscopy in the Extreme Ultraviolet
PI: Jun Ye, U of Colorado
Source: Cingoz, Nature 482, 68 (2012)
Towards dual comb EUV spectroscopy
COMB 1
COMB 2
Beat notes!
119 nm 97 nm 82 nm 47 nm 71 nm
DISTRIBUTION A: Approved for public release; distribution is unlimited
Unpublished
32
Outline
– Microresonator-based optical frequency combs
– High peak power, ultrashort pulse laser processing of materials
– Extreme ultraviolet (EUV) comb spectroscopy
– High harmonic interferometry
– Relativistic optics
DISTRIBUTION A: Approved for public release; distribution is unlimited Photo credits: DOI: 10.1038/nature05524, www.attoworld.de, E. Chowdhury (OSU)
33
High Harmonic Interferometry to follow chemical reactions
PI: Paul Corkum, NRC
Source: Worner, Nature 466, 604 (2010).
Br2
Br + Br
DISTRIBUTION A: Approved for public release; distribution is unlimited
34
Conical intersections drive the chemistry of complex molecules
Source: Paul Corkum
PI: Paul Corkum, NRC
DISTRIBUTION A: Approved for public release; distribution is unlimited AFR~I
35
Conical Intersection Dynamics in NO2
Source: Wörner, Science 334, 208 (2011)
PI: Paul Corkum, NRC
DISTRIBUTION A: Approved for public release; distribution is unlimited
100 120 140 160 180
bond angle I deg. ~
AFR~I
36
Electronic dynamics near a conical intersection
Source: Wörner, Science 334, 208 (2011)
PI: Paul Corkum, NRC
DISTRIBUTION A: Approved for public release; distribution is unlimited
A
~ -~
~ ~ r. .!21 0.4 r.
j 0.2
~ 2
11 0
13
17 0 50 100 150 200 250 300 -so
harmonic time delay (fs) order
B 0.4
;;; 0.35 c
-~ 0. 8 v c 0.3 ·c; .g 0
E o.6 -3 0.25 "' a. .s:: 0 I a. 0.2 .s::
"' v E 0. 4 "' ""0 .D 0.15 <V "' .to! '0 ;;; 0.1 E o.2 0 c 0.05
0 100 200 300 0
0 100 200
time delay (fs) time delay (fs)
D
c
300
/ / Diffraction: weak .......... stron
bond angle asym. stretch
AFR~I
37
Outline
– Microresonator-based optical frequency combs
– High peak power, ultrashort pulse laser processing of materials
– Extreme ultraviolet (EUV) comb spectroscopy
– High harmonic interferometry
– Relativistic optics
DISTRIBUTION A: Approved for public release; distribution is unlimited Photo credits: DOI: 10.1038/nature05524, www.attoworld.de, E. Chowdhury (OSU)
38
Progress in peak intensity
• Over the last two decades, a 6 order of magnitude increase in achieved focused intensities in table-top systems.
Source: CUOS website
2x1022
Relativistic ions Nonlinearity of vacuum GeV e acceleration e+e- production Nuclear reactions Relativistic plasmas Hard x-ray generation Tunnel ionization High temperature plasma formation Bright x-ray generation Nonperturbative atomic physics High order nonlinear optics Perturbative atomic physics Nonlinear Optics
DISTRIBUTION A: Approved for public release; distribution is unlimited
39
Petawatt class university lasers
University of Texas, 1.1 PW University of Nebraska, 0.7 PW
University of Michigan, 0.3 PW Ohio State University, 0.5 PW
July 16, 2012 First Light
DISTRIBUTION A: Approved for public release; distribution is unlimited
40
Laser-driven x-ray sources
• Understanding laser-generated electron beam characteristics is the key to advancing x-ray sources.
• PIC simulations of high intensity short pulse laser interacting with structured targets yields an enhancement in the number and energy of hot electron.
• Monte Carlo simulations using the electron beam source from PIC show enhancement of x-ray production.
DISTRIBUTION A: Approved for public release; distribution is unlimited
PI: Kramer Akli, OSU
Hot electron generation
Enhanced x-ray production
Picture: Courtesy of Kwei-‐Yu Chu and Lawrence Livermore National Laboratory
41
Laser-driven x-rays generation (0.1 – 10 MeV)
• Scattering from a 300 MeV electron beam can Doppler shift a 1-eV energy laser photon to 1.5 MeV energy.
• Demonstrated > 710 MeV electron beams with no detectable low-energy background.
PI: Donald Umstadter, U of Nebraska
Super Sonic Nozzle
E-Beam
Scattering Laser Pulse
Experimental geometry for generating x-rays via Thomson scattering
> 710 MeV electrons
Energy tunability from 0.1 – 0.8 GeV. Monoenergetic: ΔE/E ~ 10 %
Low angular divergence: 1-5 mrad
DISTRIBUTION A: Approved for public release; distribution is unlimited
42
Laser-driven x-rays generation (0.1 – 10 MeV)
0.5 inch thick steel plate
PI: Donald Umstadter, U of Nebraska
DISTRIBUTION A: Approved for public release; distribution is unlimited
Divergence (mrad) Counts per pixel, x t o3 - 10 Q c 4 a
"' Beam Parameter Sym Value 2 Energy £1= 0.5 Jl pulse
0 Wavelength ). 800 nm
X Pulse duration r., 90 fs (FWH M)
...... Spotsize = UL 9.4 :!: 0.4 J.llll (RMS) ..., Number of laser
Nlascr 34 Wo oscillations/pulse
s. A vcragc power PL 5.6 TW C:Jft.
e,.,"q Normalized field '!! '/1~ OQ 0.4 e,. b s trength
e/1/q Photon energy Et. I.SeV
Interaction angle <1> 170 deg
Source size Ua 6.0 :!: 2.6 J.lln (RMS)
Cutoft' energy; £, 250 MeV X 1019 e
Divergence;; o. 5 mrad (FWHM)
S' 2.5 Total charge Q 120pC v:i .._, Source size a, 5.1 :1: 2.6 J.lm (RMS)
"' "' Divergence o, 12.7 mrad (FWHM) Q) c
1::: Peak energy £, 1.2 MeV ell
·;::: Total photon co y N, -10' "' number/pulse ·:;;: ~ Peak on-axis
2.3 x I 0 19 photonsls-
§ Bx mm2-nu·dd2 (0. 1%
7d brilliance Q)
BW) p...
0·8.o 0.8 1.6 2.4 3.2 4.0 Photon Energy (Me Y)
AFR~I
43
Brighter, more energetic and tunable than conventional synchrotrons
UNL 2012
Hartemann, F. V. et al. High-energy scaling of Compton scattering light sources. Physical Review Special Topics - Accelerators and Beams 8, 100702 (2005).
PI: Donald Umstadter, U of Nebraska
DISTRIBUTION A: Approved for public release; distribution is unlimited
44
(FY14 BRI) Laser-matter interactions in the relativistic optics regime
• Laser-driven electron acceleration – Laser Wakefield Acceleration: Electrons
are accelerated to gigaelectronvolt (GeV) energies over centimeters distances
– Direct Light Acceleration
• Ion acceleration – Protons and ions are accelerated to
megaelectronvolt (MeV) energies by a mechanism known as ‘target normal sheath acceleration’ (TNSA)
• X-ray radiation sources – keV to MeV x-rays via non‐linear Thomson
Scattering – Kα monochromatic emission – Bremsstrahlung broadband radiation
• Neutron sources
– Protons incident on a secondary target (e.g. Lithium) can produce MeV neutrons
• QED physics DISTRIBUTION A: Approved for public release; distribution is unlimited
Electron density distribution and generation of quasi-monoenergetic electron bunches observed in PIC simulations.
Target Sheath Normal Acceleration: Laser acceleration of protons from the back side of a microstructured target.
45
Summary and outlook
Optical frequency combs ultra-wide bandwidths • Spectral coverage to exceed an
octave with high power/comb. • Coherence across EUV-LWIR. • Novel resonator designs (e.g.
micro-resonator based). • Ultra-broadband pulse shaping. • …
Attosecond science ultrashort pulsewidths • Efficient, high-flux generation. • Pump-probe methods. • Probe atoms/molecules &
condensed matter systems. • Attosecond pulse propagation. • Novel attosecond experiments. • Fundamental interpretations of
attosecond measurements. • …
The program aims to understand and control light sources exhibiting extreme temporal, bandwidth and peak power characteristics.
High-field laser physics high peak powers • Laser-solid interactions. • Fs propagation in media. • Sources of secondary photons. • Compact particle accelerators. • High peak power laser
architectures. • High repetition rates. • New wavelengths of operation. • …
DISTRIBUTION A: Approved for public release; distribution is unlimited