First Demonstration of Electrostatic Damping of Parametric Instability at Advanced LIGO
Name
PhysRevLett.118.151102.pdf
Size
1.22 MB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Blair, Carl
Abbott, Richard
Aston, Stuart
Betzwieser, Joseph
Blair, David
DeRosa, Ryan
Frolov, Valera
Grote, Hartmut
Hardwick, Terra
Liu, Jian
Date Issued
April 2017
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Blair, Carl et al. “First Demonstration of Electrostatic Damping of Parametric Instability at Advanced LIGO.” Physical Revew Letters 118.157 (2017): 151102–31.
Version
Final published version
Abstract
Interferometric gravitational wave detectors operate with high optical power in their arms in order to achieve high shot-noise limited strain sensitivity. A significant limitation to increasing the optical power is the phenomenon of three-mode parametric instabilities, in which the laser field in the arm cavities is scattered into higher-order optical modes by acoustic modes of the cavity mirrors. The optical modes can further drive the acoustic modes via radiation pressure, potentially producing an exponential buildup. One proposed technique to stabilize parametric instability is active damping of acoustic modes. We report here the first demonstration of damping a parametrically unstable mode using active feedback forces on the cavity mirror. A 15 538 Hz mode that grew exponentially with a time constant of 182 sec was damped using electrostatic actuation, with a resulting decay time constant of 23 sec. An average control force of 0.03 nN was required to maintain the acoustic mode at its minimum amplitude.
MIT Department
LIGO (Observatory : Massachusetts Institute of Technology)
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.118.151102
