Thermodynamical fluctuations and photo-thermal shot noise in gravitational wave antennae

TL;DR

This paper analyzes thermodynamical and optical noise sources in gravitational wave detectors, emphasizing their impact on mirror material choices and detector sensitivity.

Contribution

It identifies thermodynamical fluctuations and surface fluctuations as significant noise sources, highlighting the need to reconsider mirror materials for improved performance.

Findings

Thermodynamical fluctuations cause measurable noise in mirrors.

Optical absorption leads to surface fluctuations affecting sensitivity.

Reevaluation of mirror materials is necessary for noise reduction.

Abstract

Thermodynamical fluctuations of temperature in mirrors of gravitational wave antennae are transformed through thermal expansion coefficient into additional noise. This source of noise, which may also be interpreted as fluctuations due to thermoelastic damping, may not be neglected and leads to the necessity to reexamine the choice of materials for the mirrors. Additional source of noise are fluctuations of the mirrors' surfaces caused by optical power absorbed in dielectrical reflective layers.