Abstract
The thermal noise of mirrors in laser interferometric gravitational wave (GW) detectors is inevitable, fundamental noise and is crucial to whether a sufficiently high sensitivity to detect GWs is reached. The cryogenic mirror technique is one method to reduce the thermal noise. Japanese GW collaboration started in a study of the cryogenic mirror technique in 1997 and continues now through the Cryogenic Laser Interferometer Observatory (CLIO) project, which started in 2002. The CLIO interferometer was completed in an underground site of the Kamioka mine in 2006 as the first cryogenic interferometer for GW detection. We investigated and reduced noise of the CLIO interferometer. The cryogenic technique will be adopted for the Large-scale Cryogenic Gravitational Wave Telescope (LCGT) project, which started in 2010. This article describes the development of the CLIO interferometer and a plan for macroscopic quantum measurement using the CLIO interferometer.
