Laser system schematic
description
Transcript of Laser system schematic
![Page 1: Laser system schematic](https://reader036.fdocuments.us/reader036/viewer/2022062304/56813c7b550346895da61299/html5/thumbnails/1.jpg)
CTF3 Collaboration meeting – CERN, 16-17 January 2007
Laser system schematic
24
1.55 s
200 s, 5-50 Hz
15 kW10 J
270 s~2332 pulses370 nJ/pulse
~2332 e- bunches2.33 nC/bunch
Beam conditioner
1.5 GHzNd:YLF
oscillator
400 s, 5-50 Hz
Diode pump 18 kW pk
3 kW
2 J
3-pass Nd:YLF amplifier
x300
CWpreamp
3 pass Nd:YLF amplifier
x5
200 s, 5-50 Hz
Diode pump 22 kW pk
Optical gate (Pockels cell)
Energy stabiliser(Pockels cell)
Feedback stabilisation
Phasecoding
![Page 2: Laser system schematic](https://reader036.fdocuments.us/reader036/viewer/2022062304/56813c7b550346895da61299/html5/thumbnails/2.jpg)
CTF3 Collaboration meeting – CERN, 16-17 January 2007
Practical layout
High Qpreamp
High Qoscillator
Coding
Faraday isolator
Amp 1
Amp 2
1.54 sslicing
Noisecontrol
1 pulseslicing
HG HG
Thermallensing correction
300 cm
![Page 3: Laser system schematic](https://reader036.fdocuments.us/reader036/viewer/2022062304/56813c7b550346895da61299/html5/thumbnails/3.jpg)
CTF3 Collaboration meeting – CERN, 16-17 January 2007
Amplifier head design
Laser head assembly
Nd:YLF rod• 7mm diameter 8 cm long – Amp. 1• 10 mm diameter 11 cm long – Amp. 2• 1% doping level• Deep surface etching for higher fracture limit
Glass tube
The rod
water
Dio
des
Lens
5 Diode laser stucks• 18 kW total peak power – Amp. 1• 22 kW total peak power – Amp. 2• 400 s – Amp.1• 200 s – Amp.2
![Page 4: Laser system schematic](https://reader036.fdocuments.us/reader036/viewer/2022062304/56813c7b550346895da61299/html5/thumbnails/4.jpg)
CTF3 Collaboration meeting – CERN, 16-17 January 2007
Amplifier 1
• Amp 1 operational and tested at 5 Hz and 50 Hz
• Rod failure at 50 Hz may be due to non-saturated operation
• Expected output has been delivered (actually slightly exceeded)
• Near-field uniformity should improve with better rod
![Page 5: Laser system schematic](https://reader036.fdocuments.us/reader036/viewer/2022062304/56813c7b550346895da61299/html5/thumbnails/5.jpg)
CTF3 Collaboration meeting – CERN, 16-17 January 2007
Amplifier 1
Near-field profile is flattened by saturationbut shows some effectsof rod inhomogeneities
0 1 0 0 2 0 0 3 0 0 4 0 0
Tim e (s )
0
2 0 0
4 0 0
6 0 0
Ga
in
0
1 0 0 0
2 0 0 0
3 0 0 0
Pow
er (W
)
• Measured output from Amp 1exceeds target power (3 kW from 3 passes)
• Output saturates in agreementwith model
0 50 100 150 200 250 300 350 4000
1000
2000
3000
4000
100
200
300
400
500
Diode current: 90A
Time (microsec)
Pow
er (
W)
Gai
n
Measured at RAL Measured at CERN
![Page 6: Laser system schematic](https://reader036.fdocuments.us/reader036/viewer/2022062304/56813c7b550346895da61299/html5/thumbnails/6.jpg)
CTF3 Collaboration meeting – CERN, 16-17 January 2007
Amplifier 2
0 1 0 0 2 0 0 3 0 0 4 0 0
Time (s)
0
1 0 0 0
2 0 0 0
3 0 0 0
Ga
in0
3 0 0 0
6 0 0 0
9 0 0 0
1 2 0 0 0
Pow
er (W
)
22.8 kW
21.5 kW
2 pa ss es 20. 2 k W
1 pa ss 20 .2 k W
• 10kW from Amp 2 corresponds to 6.7J/pulse
• Beam uniformity is better than Amp 1 (fine fringes are an artefact) but rod is underfilled
• Overfilling improves saturation so steady state is reached but energy is reduced
0 1 0 0 2 0 0 3 0 0 4 0 0
Time (s)
0
1 0 0 0
2 0 0 0
3 0 0 0
Ga
in0
2 0 0 0
4 0 0 0
6 0 0 0
8 0 0 0
1 0 0 0 0
Pow
er (W
)
![Page 7: Laser system schematic](https://reader036.fdocuments.us/reader036/viewer/2022062304/56813c7b550346895da61299/html5/thumbnails/7.jpg)
CTF3 Collaboration meeting – CERN, 16-17 January 2007
Pulse slicing
-0.2
0
0.2
0.4
0.6
0.8
1
-0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
• Risetime is ~4ns
• Extinction ratio, throughput and level of induced noise remain to be optimised (noise level in above trace is misleading)
• Power handling, with additional AOM, remains to be confirmed
6 8 10 1 2 14
Time (ns)
-0.0 1
0
0.0 1
0.0 2
0.0 3
0.0 4
0.0 5
PD
Sig
nal
(V
)
• Test of 1.54s Pockels cell and driver confirms triggering and basic operation
![Page 8: Laser system schematic](https://reader036.fdocuments.us/reader036/viewer/2022062304/56813c7b550346895da61299/html5/thumbnails/8.jpg)
CTF3 Collaboration meeting – CERN, 16-17 January 2007
Frequency multiplying
• Crystals are available fortwo frequency quadruplingschemes:
2 × type I in BBO (preferred)
Type II in KTP + type I in BBO (allows two IR polarisations,perhaps for 3 GHz multiplexing)
• Tests with Amp 1 (low energy) showed an IR-UV conversion efficiency of up to 7%
Extrapolation to Amp 2 should allow system specification to be met
![Page 9: Laser system schematic](https://reader036.fdocuments.us/reader036/viewer/2022062304/56813c7b550346895da61299/html5/thumbnails/9.jpg)
CTF3 Collaboration meeting – CERN, 16-17 January 2007
Task listing
Oscillator & preamplifier Complete – April 2005
Amplifier 1 (5 Hz) Complete – April 2006
1.54 s slicing (no AOM) Demonstrated – July 2006
Amplifier 2 (5 Hz) Demonstrated – July 2006
Phase coding Designed
Frequency multiplying Demonstrated with Amp 1 – August 2006
Safety and machine protection After delivery
Coding finalisation After delivery
Frequency multiplying finalisation After delivery
Amplitude stabilisation After delivery
Single-pulse and AOM slicing After delivery
50 Hz testing After delivery
50Hz thermal lensing correction After delivery
Laser system shipped from RAL to CERN at end of August 2006
![Page 10: Laser system schematic](https://reader036.fdocuments.us/reader036/viewer/2022062304/56813c7b550346895da61299/html5/thumbnails/10.jpg)
CTF3 Collaboration meeting – CERN, 16-17 January 2007
Lasers at CERN
• Oscillator in operation – September 2006 • Preamplifier in operation after service by High Q Laser – November 2006• Amplifier 1 in operation – November 2006• Amplifier 2 assembled and tested (beams not optimized) – January 2007
2nd amplifier
Pockels cell
Breadboard
Laser beam to cathode
Phase coding
Faraday isolator
1st amplifier
HighQ oscillator
HighQ amplifier
Flipping mirrors
Beam dump
f = 300 mm
f = - 250 mm
f = -100 mm/2
f = 100 mm
f = - 150 mm
f = 400 mm
f = - 100 mm f = 800 mmBBO SHG
BBO FHG f = 300 mm
Laser beam to CALIFES
![Page 11: Laser system schematic](https://reader036.fdocuments.us/reader036/viewer/2022062304/56813c7b550346895da61299/html5/thumbnails/11.jpg)
CTF3 Collaboration meeting – CERN, 16-17 January 2007
Oscillator
PreamplifierAmplifier 1Amplifier 2
Pulse slicingPockels cell
Fiber-optics coding system
CERN installation
![Page 12: Laser system schematic](https://reader036.fdocuments.us/reader036/viewer/2022062304/56813c7b550346895da61299/html5/thumbnails/12.jpg)
CTF3 Collaboration meeting – CERN, 16-17 January 2007
Amplifiers hardware
Amplifier 2 Chillers for amplifier diodes55 l/min and 75 l/min
Drivers for 5 diode laser stucks of Amplifier 2
120 A each
![Page 13: Laser system schematic](https://reader036.fdocuments.us/reader036/viewer/2022062304/56813c7b550346895da61299/html5/thumbnails/13.jpg)
CTF3 Collaboration meeting – CERN, 16-17 January 2007
Pulse coding
EO Modulator
140.7 ns macropulses Variable
delay
Variable attenuator
140.7 + 0.333 ns delay
320 mW in from oscillator
~30 mW out to preamp
• Fibre modulation, based on telecoms technology, is fast but lossy andlimited in average power
• Measurements on the High Q system suggest 10dB loss before the preamp results in <3dB output reduction
• Delay can be adjusted by varying the fibre temperature (~0.5ps/°C)
• Attenuation can be controlled by varying the fibre bending losses
• Preliminary assembly and tests of temperature tuning were carried out at RAL
![Page 14: Laser system schematic](https://reader036.fdocuments.us/reader036/viewer/2022062304/56813c7b550346895da61299/html5/thumbnails/14.jpg)
CTF3 Collaboration meeting – CERN, 16-17 January 2007
Pulse slicing with AOM
AO Deflector
Output to
doublerPockels cell
Input from Amp 2
RF Driver
Pockels Driver
AO deflector could reducepower loading on Pockels cellby up to 80% for most ofthe macropulse
QS41-5C-S-SS2
![Page 15: Laser system schematic](https://reader036.fdocuments.us/reader036/viewer/2022062304/56813c7b550346895da61299/html5/thumbnails/15.jpg)
CTF3 Collaboration meeting – CERN, 16-17 January 2007
Laser-room DB gun 15 m 0.05 s Laser-room PB gun 75 m 0.25 sPhoto-injector Delay Loop 85 m 0.2833 s PB macro-pulse length 0.021312 sDelay Loop 42 m 0.14 sTL Delay Loop Comb. Ring 30 m 0.1 s TOTAL time 0.271312 sCombiner Ring 84 m 0.28 s Conv. 1.5 GHz to 3 GHz 0.021312 sTL Comb. ring Probe Beam 48 m 0.16 s PB selection after DB 1.860709 sTotal with 1 DL and 4.5 C. Ring 598 m 1.9933 sMacro pulse length 0.14 sFilling time of PETS+Acc. 0.02 sTOTAL time 2.1533 s
First pulse of the Drive beam Probe Beam
Timing for CLEX Probe-beam
![Page 16: Laser system schematic](https://reader036.fdocuments.us/reader036/viewer/2022062304/56813c7b550346895da61299/html5/thumbnails/16.jpg)
CTF3 Collaboration meeting – CERN, 16-17 January 2007
Thank you for your attention
AcknowledgmentsRAL
Marta DivalGraeme HirstKurdi GaborEmma SpringateBill MartinIan Musgrave
CERN
Guy SuberlucqRoberto LositoNathalie ChampaultArvind Kumar