g1300524 als amaldi10 v1 - dcc-llo.ligo.org · the$arm$length$stabilizaon$system$...

The Arm Length Stabiliza2on System for Advanced LIGO Lock Acquis2on

Adam Mullavey Louisiana State University

for the LIGO ISC

LIGO-‐G1300524 Amaldi10/GR20 Conference 7/9/2013

Acknowledgments

•  LIGO Hanford –  Daniel Sigg, Keita Kawabe, Kiwamu Izumi, Sheila Dwyer

•  LIGO Caltech –  Rana Adhikari, Koji Arai, Aidan Brooks, David Yeaton-‐Massey

•  LIGO MIT –  Peter Fritschel, MaX Evans, Lisa BarsoZ, John Miller

•  The Australian Na2onal University –  Bram Slagmolen, Daniel Shaddock, David McClelland,

•  Other –  Stefan Ballmer (Syracuse University), Alexa Staley (Columbia

University), Alberto Stochino

7/9/13 The Arm Length Stabiliza7on System for Advanced LIGO Lock Acquisi7on 2

Lock Acquisi2on


Power RecyclingMirror

BeamSplitter

Input Test Mass

X

End Test Mass

X

Input Test Mass

Y

EndTest Mass

Y

Signal RecyclingMirror

Pre-StabilizedLaser

Five Degrees Of Freedom To Sense and Control: •  DARM (Differen2al ARM) •  CARM (Common ARM) •  MICH (MICHelson) •  PRCL (Power Recycling Cavity Length) •  SRCL (Signal Recycling Cavity Length)

Difficul2es

•  Coupled Free Swinging Cavi2es –  Sensing matrix in a state of flux


S1S2•

•

SN

!

"

######

$

%

&&&&&&

=

!

"

####

$

%

&&&&

DARMCARMMICHPRCLSRCL

!

"

######

$

%

&&&&&&

Dynamic Sensing Matrix

•  Narrow locking range –  Cavity swinging too fast –  Actuators too weak to catch lock

Lock Acquisi2on

•  Simplify the problem by decoupling CARM and DARM, using independent sensors.


•  Introducing the Arm Length Stabiliza2on system

ALSDARMALSCARMS1S2•

SN

!

"

#######

$

%

&&&&&&&

=

1 0 0 0 00 1 0 0 00 0 M11 M12 M13

0 0 M21 M22 M23

• • • • •0 0 MN1 MN1 MN 3

!

"

########

$

%

&&&&&&&&

DARMCARMMICHPRCLSRCL

!

"

######

$

%

&&&&&&

Arm Length Stabiliza2on



BS

Input Test Mass

X

End Test Mass

X

Input Test Mass

Y

EndTest Mass

Y


Pre-StabilizedLaser

ALS CommX-PSL Inference

ALS DiffX-Y Inference

AuxiliaryLaser

AuxiliaryLaser

SecondHarmonicGenerator

•  Uses Auxiliary Lasers locked to the Arm Cavi2es

•  TransmiXed Aux light combined with doubled PSL to form a heterodyne signals

End Sta2on

The Arm Length Stabiliza7on System for Advanced LIGO Lock Acquisi7on 7/9/13 7

EndTest Mass

Auxiliary Laser

Servo

PhaseModulator

PhaseFrequency

Discriminator

40MHz

24MHz

PSL Light viaOptical Fiber

Laser Locking LoopUGF~30kHz

PDH LoopUGF~10kHz

Servo

•  Auxiliary Laser –  Dual Wavelength (532nm and 1064nm) –  First Locked to PSL –  Locked to Arm Cavity, via PDH technique and fed back to 40MHz VCO

ALS -‐ Corner Sta2on


ALS Diff(X-Y Inference)

Input Mode Cleaner


BeamSplitter

InputTest Mass

X

ALS Comm(X-PSL Inference)

PhaseModulator

ServoPhase

FrequencyDiscriminator

PhaseFrequency

Discriminator

Pre-Stabilised Laser

Second Harmonic Generator

80MHz +Offset

InputTest Mass

Y

Servo

160MHz +Offset

Differentially to End

Test Masses

•  ALS Comm –  fed back to PSL frequency (via IMC) –  Offset injected into loop for tuning

of resonance

•  ALS Diff –  fed back differen2ally to ETMs

Prototype Experiments

•  Couple of experiments to test out ALS technique on single cavity: –  ANU Benchtop Experiment ([1] Mullavey et. Al) –  Caltech 40m Experiment ([2] Izumi et. al)


ANU Benchtop Experiment


Tip Tilt 2

15MHz

10MHz

Tip Tilt Mirror Control (CDS)

ALSgain

IR PDHgain

ADC

ADC

DAC

DAC

DAC

ADCAuxiliary LaserLocking FPGA

Relative FrequencyMeasurement FPGA

FrequencyO!set

AuxiliaryLaser

532nm1064nm

Tip Tilt 1

CavityController

ADC

EOM

EOM

ScienceLaser

1064nm

•  1.3m cavity •  Suspended mirrors •  Beatnote from

1064nm, not 532nm •  Feedback to arm

length not Science Laser

ANU Bench-‐top Results


Mullavey et al

30pm RMS, approx 1/30th cavity line-‐width

-20 0 20 40 60 80 100 120 1400

0.5

1

Pow

er (a

rb)

-20 0 20 40 60 80 100 120 140-1

0

1

Sign

al (a

rb)

-20 0 20 40 60 80 100 120 1400

0.5

1

Frequency Offset (MHz)

Pow

er (a

rb)

Tuneable over full free spectral range

Caltech 40m Experiment

•  40m cavity •  Beatnote from 532nm

•  Feedback to arm length


Caltech 40m Results


Izumi et. al. 24pm RMS

24 pm RMS

Tuning On and Off Resonance

Progress at the Sites

•  Hanford – Y sta2on ALS installed and commissioned (One Arm Test)

– Half Interferometer (HIFO) test, i.e. effec2vely ALS-‐Comm loop

•  Livingston – Basically nothing yet (wai2ng for an arm)



BS

Input Test Mass

Y

EndTest Mass

Y


Pre-StabilizedLaser

ALS CommY-PSL Inference

AuxiliaryLaser

SHG

Hanford HIFO test

•  Beat signal between Y-‐ARM and doubled PSL

•  Using actual LIGO ALS system: electronics, etc.

•  Feeding back to PSL (via IMC)


HIFO Residual Noise


Frequency (Hz)-210 -110 1 10 210

)1/

2Fr

eque

ncy

Fluc

tuat

ion

(Hz/

Hz

-110

1

10

HIFO-Y Frequency Noise

T0=29/06/2013 04:00:00 Avg=10/Bin=11L BW=0.0117178

IR transmitted lightRMS

HIFO-Y Frequency Noise

1/10 the linewidth of the arm cavity

Future

•  Hanford – Con2nue Noise Hun2ng, < CARM linewidth (100 2mes smaller than Arm Linewidth)

– HIFO X (soon) – Full IFO (May 2014)

•  Livingston – HIFO X (October 2013) – Full IFO (February 2014)


References


[1] Mullavey et. al, Op2cs Express, Vol 20, Issue 1, pp 81-‐89 (2012)

[2] Izumi et. al, JOSA A, Vol. 29, Issue 10, pp. 2092-‐2103 (2012)

Backup Slides


g1300524 als amaldi10 v1 - dcc-llo.ligo.org · the$arm$length$stabilizaon$system$...

Documents