Download Characterization of LIGO Input Optics (Haisheng Rong

Characterization of LIGO Input Optics
University of Florida
Caltech
MIT
Thomas Delker
Guido Mueller
Malik Rakhmanov
David Reitze
Haisheng Rong
Qi-ze Shu
David Tanner
Sanichio Yoshida
Jordan Camp
Bill Kells
Nergis Mavalvala
David Ottaway
Daniel Sigg
Stan Whitcomb
Rana Adhikari
Peter Fritschel
Mike Zucker
Presented by Haisheng Rong at
LSC Meeting 7
Hanford, 15-17 August 2000
Laser Interferometer Gravitational-wave Observatory
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Input Optics System

Primary Functions of the IO System
 Conditioning of the PSL output
 Frequency, Intensity and beam pointing stability
 Filter high-order modes
 Mode matching and beam delivery
 Optical isolation
 RF sidebands generation for IFO sensing
Laser Interferometer Gravitational-wave Observatory
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Input Optics Components
IFO
Laser Interferometer Gravitational-wave Observatory
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IO System Interfaces
Laser Interferometer Gravitational-wave Observatory
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Status of the IO System

LHO 2k
»
»
»
»

Operational since 08/99
Major characterization measurements finished
Integration with 2k IFO arm cavity successful
Modification and realignment 04/00 – 05/00
LLO 4k
» Mode cleaner locked in 03/00
» Characterization and improvement 03/00 – 06/00
» IO realignment 06/00 – 08/00

LHO 4k
» Installation started 07/00
Laser Interferometer Gravitational-wave Observatory
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Characterization Measurements

Mode Cleaner Length
» Measured with RF resonant side band detuning method.
» Uncertainty / Drift ~ 3ppm (50 mm)
» Position Accuracy < 1mm

MC Transmission
» 0.98  0.05

Mode Matching into the 2k Arm Cavity
» Power Coupling: 95%-98%
Laser Interferometer Gravitational-wave Observatory
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Characterization Measurements

MC Output Beam Pointing Stability
» Long-term drift
~4mrad/hr
» Beam jitter
10 -10 rad/rtHz
at f >20Hz
Laser Interferometer Gravitational-wave Observatory
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Characterization Measurements

MC cavity linewidth measurements
Ringdown
Transfer function
Laser Interferometer Gravitational-wave Observatory
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Characterization Measurements

MC linewidth measurement results
Laser Interferometer Gravitational-wave Observatory
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Characterization Measurements

Internal Q’s of MC mirrors
Laser Interferometer Gravitational-wave Observatory
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MC - a sensitive analyzer cavity

Frequency noise of the PSL
Laser Interferometer Gravitational-wave Observatory
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Effect of the vertical mirror motion

PSD of MC length control signal
F = 0.62 mrad
F=0
F: Angle of MC plane
wrt. horizontal
Laser Interferometer Gravitational-wave Observatory
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Frequency noise of MC output

Frequency noise measured with 2k FP arm cavity
Laser Interferometer Gravitational-wave Observatory
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Coming up

Lock MC at designed input power
» Scattered laser light interacts with suspension local
sensors, causing angular instability
» Solution
– Phase sensitive detection (coherent sensor)
– New shadow sensors
Laser Interferometer Gravitational-wave Observatory
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