Compensation for thermal effects in mirrors of Gravitational Wave Interferometers

TL;DR

This paper explores methods to mitigate thermal lensing in gravitational wave interferometer mirrors by heating cold mirror parts, suggesting combined thermal compensation and alternative materials like Sapphire for future detector upgrades.

Contribution

It introduces and evaluates thermal compensation techniques involving heating mirror parts and proposes using alternative substrate materials such as Sapphire for improved performance.

Findings

Thermal compensation significantly reduces thermal lensing effects.

Combining thermal compensation with new substrate materials enhances mirror performance.

Pure thermal compensation cannot fully eliminate thermal effects.

Abstract

In this paper we study several means of compensating for thermal lensing which, otherwise, should be a source of concern for future upgrades of interferometric detectors of gravitational waves. The methods we develop are based on the principle of heating the cold parts of the mirrors. We find that thermal compensation can help a lot but can not do miracles. It seems finally that the best strategy for future upgrades (``advanced configurations'') is maybe to use thermal compensation together with another substrate materials than Silica, for example Sapphire.