b. willke, mar 01 ligo-g010114-00-z laser developement for advanced ligo benno willke lsc meeting...
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LIGO-G010114-00-Z B. Willke, Mar 01
Laser Developement for Advanced LIGO
Benno Willke
LSC meeting
LIGO-Livingston Site, Mar 2001
LIGO-G010114-00-Z B. Willke, Mar 01
LIGOII PSL – requirements
Fourier Frequency (Hz)
Frequency Noise Spectral Density
(Hz/Hz1/2)
10 10
100 1
1k 10-1
10k 10-2
Fourier Frequency (Hz)
Power Noise Spectral Density (1/Hz1/2)
10 10-6
100 10-7
1k 10-7
10k 10-7
25MHztechnical noise <10%
shot noise of 1W
• 180W in gausian TEM00 mode
• less than 10W in non - TEM00 modes
LIGO-G010114-00-Z B. Willke, Mar 01
LIGOII PSL – subsystem layout
front end powerstages
modecleaner
pre-mode
cleaner
referencecavity
long baselinecavities
20W 200W
180W
frequency stabilization
power stabilizaiton
LIGO-G010114-00-Z B. Willke, Mar 01
LIGOII PSL – project stages
• develop concepts
• design and build laboratory version
• design and build final version
• PSL fabrication
• PSL installation
LIGO-G010114-00-Z B. Willke, Mar 01
develop concepts
• increase power of front-end
• evaluate high-power-stage concepts– MOPA slab (Stanford)– stable-unstable slab oscillator (Adelaide)– rod systems (Hannover)
• test power and frequency stabilization schemes
LIGO-G010114-00-Z B. Willke, Mar 01
Nd:YAG Master-Laser
NPRO (non-planar ring oscillator) by Innolight*
• output power: 800mW
• frequency noise: [ 10kHz/f ] Hz/sqrt(Hz)
• power noise: 10-6 /sqrt(Hz)
* US dristibution: Resonant optics Corp., San Martin CA
LIGO-G010114-00-Z B. Willke, Mar 01
GEO 600 Slave Laser Prototype IIFrequency Stability
1 10 100 1000 10000 10000010
-1
100
101
102
103
104
105
106
quasi monolithic slave relative to stabilized NPRO (inj.-lock actuator signal)
discrete component slave (ditto) free running NPRO
relative to a reference cavity
Fre
que
ncy
Flu
ctua
tions
[H
z/H
z1/2 ]
Frequency [Hz]
LIGO-G010114-00-Z B. Willke, Mar 01
Power Scaling of End Pumped Nd:YVO4
0 5 10 15 20 25 30 35 400
2
4
6
8
10
12
14
16
18
GEO slave with standard Nd:YVO4 "rods"
brewsterplates removed
outp
ut p
ower
[W]
pump power [W]
Advantages of Nd:YVO4 1)
• amplifies 1064 nm emission of Nd:YAG (basic requirement)
• birerefingence na= 1.96 / nc= 2.17 no depolarization
• emission || = 25x10-19 cm-2 = 7x10-19 cm-2
polarized emission• large product of || sp (sp 90 s)
loss insensitive high gain lasers• 8 nm broad absorption @ 808 nm
low requirements on pump diodes
Disadvantage of Nd:YVO4 1)
• low pump intensity damage threshold58 W / mm2 @ 0.5 % doping29 W / mm2 @ 1.0 % dopingincreased by 50 % by undoped endcaps
1) Data from Y.-F. Chen, IEEE J. Q. E. 35(2), 234 (1999) / Tsunekane et. al. Elt. Lett. 32(1), 41 (1996) / VLOC, Casix, Castech web pages
LIGO-G010114-00-Z B. Willke, Mar 01
PBS
/4
DeformableMirror
Injection-locked
osc. (20 W)
WavefrontSensor
Mode-matchinglenses
Mode-matchinglenses
To Mode-Cleaner(s)
AmplifierStage 1
AmplifierStage 2
Stanford MOPA design
LIGO-G010114-00-Z B. Willke, Mar 01
results Stanford Jan01
• 12W injection locked laser was shipped to
Stanford and showed stable operations
• 27W stable operation of first ampl. stage
• some fluid (oil ?) developed on the entrance
surface of second ampl. slab and degraded
its performance for powers above 35W
LIGO-G010114-00-Z B. Willke, Mar 01
design and build lab-version
• design reliable laser heads for power stages
• include suitable actuators in laser design
• integrate stabilized front-end, high-power-stages and pre-modecleaner
• design power stabilization (in-loop test)
LIGO-G010114-00-Z B. Willke, Mar 01
design and build final version
• optimize design according to lessons learned with lab-version and including system aspects like reliability, safety, robustness, automation and system interfaces (DAQ, power, cooling, ...)
• keep flexibility to react on long-term behavior of lab-version
LIGO-G010114-00-Z B. Willke, Mar 01
PSL fabrication & installation
• quality check
• system integration (if components are fabricated at different locations)
• reproducibility
• user training
LIGO-G010114-00-Z B. Willke, Mar 01
Laser Zentrum Hannover
Max-Planck InstitutUniversity of GlasgowUniversity of Hannover
GEO600 pre-stabilized laser
High-power solid- state-lasers design
power and frequency stabilization
LIGOII pre-stabilized laser
LIGO LabStanford
Adelaide
the LIGOII laser-team
LIGO-G010114-00-Z B. Willke, Mar 01
LIGOII laser-team
• 4 FTE Laser Zentrum Hannover – Fallnich, Ralf, Ivo, Mike, Martina
• 1 FTE Stanford - Rutherford • 1 FTE Adelaide - Veitch • 3 FTE University Hannover/Max-Planck-Group
– Willke, Kirchner, Weidner, Nagano• 1 FTE Glasgow
– Ward, Robertson• 1 FTE LIGO
– King, Abbott• workshop support Hannover / CDS
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