Thermal noise reduction in CLIO was published in Physical Review Letters

Thermal noise reduction in CLIO was published in Physical Review Letters.

Summary by Author T.Uchiyama.

“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 stabilisation 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 mirror’s 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), the construction of which began in 2010 in Japan, and the Einstein Telescope in Europe.”