Reduction and possible elimination of coating thermal noise using a rigidly controlled cavity with a QND technique

TL;DR

This paper proposes a novel method to significantly reduce or potentially eliminate coating thermal noise in high-precision measurements by using a rigidly controlled cavity combined with a quantum-non-demolition technique, surpassing the standard quantum limit.

Contribution

It introduces a new approach to suppress coating thermal noise through mechanically separated mirrors and QND techniques, advancing beyond previous mechanical separation methods.

Findings

Thermal noise can be reduced by mechanically separating mirror layers.

Quantum-non-demolition techniques can overcome control noise limits.

Complete elimination of coating thermal noise is theoretically possible.

Abstract

Thermal noise of a mirror is one of the most important issues in high precision measurements such as gravitational-wave detection or cold damping experiments. It has been pointed out that thermal noise of a mirror with multi-layer coatings can be reduced by mechanical separation of the layers. In this paper, we introduce a way to further reduce thermal noise by locking the mechanically separated mirrors. The reduction is limited by the standard quantum limit of control noise, but it can be overcome with a quantum-non-demolition technique, which finally raises a possibility of complete elimination of coating thermal noise.