A study for reduction of radiation pressure noise in gravitational wave detectors
We describe an experimental conceptual design for observation and reduction of radiation pressure noise. The radiation pressure noise is increased in a high finesse cavity with a small mass mirror. In our experiment a Fabry-Perot Michelson interferometer with a homodyne detection scheme will be built with Fabry-Perot cavities of finesse of 10000 containing suspended mirrors of 23 mg. To observe the radiation pressure noise, the goal sensitivity is set to 1×10^(-17) [m/√Hz] at 1 kHz. Then the radiation pressure noise is reduced by adjusting the homodyne phase. To achieve the sensitivity, the other noise sources such as thermal noises, seismic noise and laser frequency noise should be suppressed below 1×10^(-18) [m/√Hz] at 1kHz. The whole interferometer is suspended as a double pendulum on double-layer stacks. As a preliminary setup, a Fabry-Perot cavity of finesse of 800 with a suspended mirror of 100 mg was locked. The current best sensitivity is 1×10^(-15) [m/√Hz] at 1 kHz.
© 2008 IOP Publishing Ltd. The authors would like to thank engineers of the machine shop at National Astronomical Observatory of Japan for making special components of the suspension with the 100 mg mirror and the seismic isolation systems. The research is supported in part by the United States National Science Foundation grant PHY-0107417 for the construction and operation of the LIGO Laboratory and the Science.
Published - SAKjpcs08.pdf