Parametric instabilities and their control in advanced interferometer gravitational-wave detectors

A detailed simulation of Advanced LIGO test mass optical cavities shows that parametric instabilities will excite 7 acoustic modes in each fused silica test mass, with parametric gain R up to 7 and only 1 acoustic mode with R approximately 2 for alternative sapphire test masses. Fine-tuning of the t...

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Bibliographic Details
Published inPhysical review letters Vol. 94; no. 12; p. 121102
Main Authors Zhao, C, Ju, L, Degallaix, J, Gras, S, Blair, D G
Format Journal Article
LanguageEnglish
Published United States 01.04.2005
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Summary:A detailed simulation of Advanced LIGO test mass optical cavities shows that parametric instabilities will excite 7 acoustic modes in each fused silica test mass, with parametric gain R up to 7 and only 1 acoustic mode with R approximately 2 for alternative sapphire test masses. Fine-tuning of the test mass radii of curvature causes the instabilities to sweep through various modes with R as high as approximately 2000. Sapphire test mass cavities can be tuned to completely eliminate instabilities using thermal g-factor tuning. In the case of fused silica test mass, instabilities can be minimized but not eliminated.
ISSN:0031-9007
DOI:10.1103/PhysRevLett.94.121102