Measurement of the mechanical loss of a cooled reflective coating for gravitational wave detection

Abstract

We have measured the mechanical loss of a dielectric multilayer reflective coating (ion-beam sputtered SiO${}_2$ and Ta${}_2$O${}_5$) in cooled mirrors. The loss was nearly independent of the temperature (4 K $\sim$ 300 K), frequency, optical loss, and stress caused by the coating, and the details of the manufacturing processes. The loss angle was $(4\sim 6)\times 10^{-4}$. The temperature independence of this loss implies that the amplitude of the coating thermal noise, which is a severe limit in any precise measurement, is proportional to the square root of the temperature. Sapphire mirrors at 20 K satisfy the requirement concerning the thermal noise of even future interferometric gravitational wave detector projects on the ground, for example, LCGT.

8 pages, 6 figures, 3 tables : accepted version (by Physical Review D)

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Cited by in corpus (15)

• Detector configuration of KAGRA - the Japanese cryogenic gravitational-wave detector
• Measurements of a low temperature mechanical dissipation peak in a single layer of Ta2O5 doped with TiO2
• Reduction of thermal fluctuations in a cryogenic laser interferometric gravitational wave detector
• Excess noise and photo-induced effects in highly reflective crystalline mirror coatings
• Evaluation of heat extraction through sapphire fibers for the GW observatory KAGRA
• An ultra-low dissipation micro-oscillator for quantum opto-mechanics
• Thermal noise and mechanical loss of SiO${}_2$/Ta${}_2$O${}_5$ optical coatings at cryogenic temperatures
• Coating thermal noise of a finite-size cylindrical mirror
• Technology for the next gravitational wave detectors
• Particle swarm optimization of the sensitivity of a cryogenic gravitational wave detector
• Effect of energy deposited by cosmic-ray particles on interferometric gravitational wave detectors
• Inhomogeneous mechanical losses in micro-oscillators with high reflectivity coating
• Parametric instabilities in the LCGT arm cavity
• A new method of probing mechanical losses of coatings at cryogenic temperatures
• Folding Gravitational-Wave Interferometers