Theoretical analysis of mechanical displacement measurement using a multiple cavity mode transducer

TL;DR

This paper introduces a multi-cavity optomechanical transducer that enhances displacement measurement sensitivity and quantum backaction control by utilizing multiple coupled cavity modes, enabling quantum limit achievement at lower power.

Contribution

It provides a theoretical framework for using multiple cavity modes in optomechanical sensors to improve sensitivity and enable quantum backaction noise cancellation.

Findings

Enhanced sensitivity and quantum backaction at lower input power.

Coupling between cavity modes via reservoir interaction.

Potential for experimental implementation in optical and microwave systems.

Abstract

We present an optomechanical displacement transducer, that relies on three cavity modes parametrically coupled to a mechanical oscillator and whose frequency spacing matches the mechanical resonance frequency. The additional resonances allow to reach the standard quantum limit at substantially lower input power (compared to the case of only one resonance), as both, sensitivity and quantum backaction are enhanced. Furthermore, it is shown that in the case of multiple cavity modes, coupling between the modes is induced via reservoir interaction, e.g., enabling quantum backaction noise cancellation. Experimental implementation of the schemes is discussed in both the optical and microwave domain.