Talk detail

Participant	Miyoki, Shinji
Institution	ICRR, The University of Tokyo - 5-1-5, Kashiwanoha - Kashiwa - Chiba - Japan

Session	GW4	Accepted		Order	Time
Talk	Oral abstract	Title	Thermal noise reduction in Cryogenic Laser Interferometer Observatory (CLIO)
Co-authors
Abstract	Thermal fluctuation, as evidenced by Brownian motion, has been a well-known phenomenon, and it remains the fundamental limitation for certain ultraprecise measurements such as interferometric gravitational wave (GW) detectors and laser frequency stabilization using a rigid Fabry-Perot reference cavity. One promising approach for reducing such fluctuations is to use a low-mechanical-loss material at a low temperature. Here, we experimentally demonstrate for the first time a reduction in a mirrorfs thermal fluctuation in a GW detector with suspended sapphire mirrors from the Cryogenic Laser Interferometer Observatory (CLIO) at 17K and 18K. The majority of previous efforts to reduce thermal fluctuations in such mirrors have focused on the use of low-loss materials at room temperature. Thus, this achievement provides a new method for overcoming the limitations by thermal fluctuations at room temperature. This cryogenic mirror technology will be used in advanced GW detectors such as KAGRA formerly called the Large-Scale Cryogenic Gravitational Wave Telescope (LCGT). We would like to summarize the stable performance of 20-m FP type interferometer which was built in Kamioka mine ahead of CLIO, and to talk about thermal noise reduction demonstration of CLIO.