Status of the Advanced LIGO PSL development
LSC meeting, Baton Rouge March 2007
G070137-00-Z
Benno Willke
for the PSL team
2
Advanced LIGO prestabilized laser
mediumpowerstage
highpowerstage
NPRO
referencecavity
AOM
pre-modecleaner
to interferometer
3
development and fabrication plan
functional
prototype
laboratory
prototype engineeringprototype ( LASTI )
engineering
prototype
laboratory
prototype
functional
prototype
functional
prototype
stabilization
development
laser
development
integrationlaser – stabilization
laboratory prototype: demonstrate concepts
functional prototype: demonstrate specs
engineering prototype: fit / form / function
front end LP front end FP front end EP front end RS front end #1, #2
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status March 2007
AEI funding is approved
contract between AEI and LZH is in place
fully staffed (7 people @ LZH, 4 people @ AEI, spending money)
LZH labs renovated
first NPROs for the observatories arrived
first Enhanced LIGO type laser will be delivered early summer
MOU between AEI and LIGO Lab is in preparation
new air condition 15-20 air changes higher temperature stability Class 1000 Filter
airlock particle counts:
floor: > 50.000 lab: ~ 2.000 table: 0
120 kVA UPS
5
Advanced LIGO prestabilized laser
mediumpowerstage
highpowerstage
NPRO
referencecavity
AOM
pre-modecleaner
to interferometer
6
Innolight Mephisto
4 out of 8 Master lasers (2W NPROs) are delivered they have a special interface characterization program
power, slope, power in p-pol RIN:
noise spectrum 1Hz – 100kHz, time series (60min) rms
frequency noise spectrum 1Hz – 100kHz upper limit for drift
PZT and slow actuator calibration beam quality
higher order mode content beam pointing
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Advanced LIGO NPRO characterization
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amplifier design
Crystal: 3 x 3 x 10 mm3 Nd:YVO4 8 mm 0,3 % dot.2 mm undoped endcap
Pump diode: 808 nm, 45 W400 µm fiber diameterNA=0,22
amplifier: 38W for 2W seed and 150W pump
Pump-optics
Watercooled copper holder
Nd:YVO4YVO4
Indiumfoil
dichroic mirror
Fiber-coupledPumpdiode
NPRO
/4
/2
NPRO
Isolator
Nd:YVOcrysta ls
4
pum poptics
Frede et al, Opt. Express 22 p459 (2007)
9
Advanced LIGO 35W front-end
front end will be assembled on breadboard and delivered in single housing
AOM and isolators included
NPRO and amplifier controlled via Beckhoff touchpad
interface to EPICS
0 2 4 6 8 10 12 14 1620
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22
23
24
25
26
27
28
29
30
31
32
33
34
35
crystal holder temperature
room temperature
Flowbox openedAir Conditioning off
Outp
ut
Pow
er (
W)
tem
pe
ratu
re (
°C)
time (h)
30
37,0
37,5
38,0
38,5
39,0
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front end – pump power and control
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High Power Stage
mediumpowerstage
highpowerstage
NPRO
referencecavity
AOM
pre-modecleaner
to interferometer
12
lab prototype – changes since last year
changed front-end to Enhanced LIGO design optimize resonator design identify critical components improve beam quality improve injection locking current state:
150W output power; 85% in TEM0,0
13
error signals 12MHz vs. 35MHz
190 200 210 220 230 240 250
-2,0
-1,5
-1,0
-0,5
0,0
0,5
1,0
1,5
2,0
12MHz
Am
plit
ude [
a.u
.]
Piezo voltage [V]220 240 260 280 300 320 340
-2,0
-1,5
-1,0
-0,5
0,0
0,5
1,0
1,5
2,0
35MHz
Am
plit
ude
[a.u
.]
Piezo voltage [V]
140 150 160 170 180 190 200
-2,0
-1,5
-1,0
-0,5
0,0
0,5
1,0
1,5
2,0
12MHzA
mplit
ude
[a.u
.]
Piezo voltage [V]
120 140 160 180 200 220 240 260 280 300-1,5
-1,0
-0,5
0,0
0,5
1,0
1,5
35Mhz
Am
plit
ude
[a.u
.]
Piezo voltage [V]
improved isolation
14
noise performance of lab prototype
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pump-chamber design: RIN/ water flow
1 10 100 1000 10000 1000001E-8
1E-7
1E-6
1E-5
1E-4
1E-3 1300ccm 1000ccm 750ccm 600ccm 500ccm
Frequenz (Hz)
RIN
(1/H
Z-1
/2)
1 10 100 1000 10000 1000001E-8
1E-7
1E-6
1E-5
1E-4
1E-3 Pumpkammer Alt Pumpkammer Neu 1300ccm
Frequenz (Hz)
RIN
(1/H
Z-1
/2)
3872 Hz
3600 Hz
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functional prototype
7 instead of 10 fibers
7 x 45 W
new homogenizer
higher pump brightness
new laser head design
whole resonator on base plate
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improved laser head design
X-Y-Z translation and rotation stage for crystal alignment
ceramic parts to prevent moving due to heat-load from spraylight
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status of functional prototype
front end components in house, setup starts next
week high power stage
mechanical design ready components in mechanical workshop diode boxes currently build
standing wave resonator test new fiber design works high brightness pumping gives similar
results as achieved with 10 diodes 90W TEM0,0 output power
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frequency stabilization
shutter
mediumpowerstage
highpowerstage
NPRO
referencecavity
AOM
spatialfilter
cavity
shutter
variableattenuatorwith powermeter
AOM
EOM FI FI
101
102
103
104
10-2
10-1
100
Frequency (Hz)
Fre
qu
ency
No
ise
(Hz/
Hz1
/2)
20
PMC design
thermal loading PMC design based on
thermal loading experiment by A. Bullington (Stanford)
assumption: less than 3ppm absorption
allow for a total of 10mW absorbed power
finesse 50 (3kW circulating power)
in sealed housing, vacuum required ?
rf filtering 4dB @9MHz sufficient? , increase length?
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power stabilization
Seifert et al., Opt. Lett. 31 (2006) 2000
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diagnostic bread board
shutter
mediumpowerstage
highpowerstage
NPRO
referencecavity
AOMPSL internalDiagnostic
spatialfilter
cavity
shutter
variableattenuatorwith powermeter
powermeter
shutter
AOM
EOM FI FI
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PZT
PZT M2
PZT M1
Laser
PD
beam diagnostic setup
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NPRO (filtered by a fiber and PMC)
Finesse: 366 ±5higher order mode power: 0.56% ±0.3%
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Gaussian mode expansion
PZT
3,9%0,9% 0,8% 0,8%
=
10%
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beam pointing
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RIN – Advanced LIGO NPRO
noise eater off noise eater off
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location and control - Enhanced LIGO
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location and control - Advanced LIGO
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Advanced LIGO PSL setup