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

4

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

7

Advanced LIGO NPRO characterization

8

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

21

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

10

front end – pump power and control

11

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

15

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

16

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

17

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

18

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

19

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?

21

power stabilization

Seifert et al., Opt. Lett. 31 (2006) 2000

22

diagnostic bread board

shutter

mediumpowerstage

highpowerstage

NPRO

referencecavity

AOMPSL internalDiagnostic

spatialfilter

cavity

shutter

variableattenuatorwith powermeter

powermeter

shutter

AOM

EOM FI FI

23

PZT

PZT M2

PZT M1

Laser

PD

beam diagnostic setup

24

NPRO (filtered by a fiber and PMC)

Finesse: 366 ±5higher order mode power: 0.56% ±0.3%

25

Gaussian mode expansion

PZT

3,9%0,9% 0,8% 0,8%

=

10%

26

beam pointing

27

RIN – Advanced LIGO NPRO

noise eater off noise eater off

28

location and control - Enhanced LIGO

29

location and control - Advanced LIGO

30

Advanced LIGO PSL setup