Thermo-optic noise in coated mirrors for high-precision optical measurements

TL;DR

This paper analyzes thermo-optic noise in mirror coatings, highlighting its impact on high-precision optical measurements like gravitational wave detection and providing a comprehensive model including finite coating effects.

Contribution

It presents a coherent treatment of thermo-elastic and thermo-refractive mechanisms, including finite coating thickness corrections, for improved noise modeling in advanced gravitational wave detectors.

Findings

Thermo-optic noise is a significant limit in high-precision optical measurements.

Finite coating thickness affects the magnitude of thermo-optic noise.

Implications for Advanced LIGO are quantitatively evaluated.

Abstract

Thermal fluctuations in the coatings used to make high-reflectors are becoming significant noise sources in precision optical measurements and are particularly relevant to advanced gravitational wave detectors. There are two recognized sources of coating thermal noise, mechanical loss and thermal dissipation. Thermal dissipation causes thermal fluctuations in the coating which produce noise via the thermo-elastic and thermo-refractive mechanisms. We treat these mechanisms coherently, give a correction for finite coating thickness, and evaluate the implications for Advanced LIGO.