Minimum Noise Optical Coatings for Interferometric Detectors of Gravitational Waves

TL;DR

This paper discusses strategies for reducing coating Brownian noise in gravitational wave detectors, emphasizing layer thickness optimization as an effective and experimentally validated approach to enhance detector sensitivity.

Contribution

It introduces and validates a layer thickness optimization method for minimizing coating noise, advancing the design of more sensitive gravitational wave detectors.

Findings

Layer thickness optimization reduces coating noise effectively.

Experimental results confirm theoretical predictions.

Design robustness improves detector performance.

Abstract

Coating Brownian noise is the dominant noise term, in a frequency band from a few tens to a few hundreds Hz, for all Earth-bound detectors of gravitational waves. Minimizing such noise is mandatory to increase the visibility distance of these instruments, and eventually reach their quantum limit. Several strategies are possible to achieve this goal. Layer thickness optimization is the simplest option, yielding a sensible noise reduction with limited technological challenges. Experimental results confirm the accuracy of the underlying theory, and the robustness of the design.