Angular control of optical cavities in a radiation pressure dominated regime: the Enhanced LIGO case

We describe the angular sensing and control of the 4 km detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO). The culmination of first generation LIGO detectors, Enhanced LIGO operated between 2009 and 2010 with about 40 kW of laser power in the arm cavities. In this regime, r...

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Bibliographic Details
Published in:arXiv.org 2013-10
Main Authors: Dooley, Katherine L, Barsotti, Lisa, Adhikari, Rana X, Evans, Matthew, Fricke, Tobin T, Fritschel, Peter, Frolov, Valera, Kawabe, Keita, Smith-Lefebvre, Nicolás
Format: Article
Language:English
Subjects:
Detectors
Gravitational waves
Holes
LIGO (observatory)
Pressure effects
Radiation pressure
Transfer functions
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Summary:We describe the angular sensing and control of the 4 km detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO). The culmination of first generation LIGO detectors, Enhanced LIGO operated between 2009 and 2010 with about 40 kW of laser power in the arm cavities. In this regime, radiation pressure effects are significant and induce instabilities in the angular opto-mechanical transfer functions. Here we present and motivate the angular sensing and control (ASC) design in this extreme case and present the results of its implementation in Enhanced LIGO. Highlights of the ASC performance are: successful control of opto-mechanical torsional modes, relative mirror motions of 1x10^{-7} rad rms, and limited impact on in-band strain sensitivity.
ISSN:2331-8422
DOI:10.48550/arxiv.1310.3662