Thermal lensing in cryogenic sapphire substrates

Abstract

We report the reduction of the thermal lensing in cryogenic sapphire mirrors, which is planed to be used in the Large scale Cryogenic Gravitational wave Telescope (LCGT) project. We measured three key parameters of sapphire substrate for thermal lensing at cryogenic temperature. They are optical absorption coefficient, thermal conductivity and temperature coefficient of refractive index at cryogenic temperature. On basis of these measurements, we estimated the shot noise sensitivity of the interferometer with thermal lensing by using a wave-front tracing simulation. We found that thermal lensing in cryogenic sapphire mirrors is negligible.

6 pages, 3 figures, Proceedings of 4th Edoaldo Amaldi Conference of Gravitational Waves, 8 - 13 July 2001, The University of Western Australia. Accepted to Classical and Quantum Gravity (Special Issue)

References in corpus (1)

• Cryogenic measurement of the optical absorption coefficient in sapphire crystals at 1.064(micro)m for the Large-scale Cryogenic Gravitational wave Telescope

Cited by in corpus (10)

• Reduction of thermal fluctuations in a cryogenic laser interferometric gravitational wave detector
• Performance of the KAGRA detector during the first joint observation with GEO 600 (O3GK)
• Technology for the next gravitational wave detectors
• Mirror thermal noise in laser interferometer gravitational wave detectors operating at room and cryogenic temperature
• Effect of energy deposited by cosmic-ray particles on interferometric gravitational wave detectors
• Grid-based simulation program for gravitational wave interferometers with realistically imperfect optics
• Simulating a dual-recycled gravitational wave interferometer with realistically imperfect optics
• Parametric instabilities in the LCGT arm cavity
• Analysis of a four-mirror cavity enhanced Michelson interferometer
• Thermal lensing measurements of Ti: Sapphire crystal pumped at 80 MHz picosecond pulses by Shack-Hartmann wavefront sensor