Proposal for a near-field optomechanical system with enhanced linear and quadratic coupling

TL;DR

This paper proposes a near-field optomechanical system with high cooperativity and enhanced quadratic coupling, enabling low-light quantum nonlinear effects and precise phonon measurements.

Contribution

It introduces a realistic hybrid system with separated optical and mechanical modes achieving unprecedented cooperativity and stronger quadratic coupling than previous setups.

Findings

Single-photon cooperativity exceeds 300.

Enhanced quadratic optomechanical coupling surpassing previous records.

Potential for low-light quantum nonlinear applications.

Abstract

We propose a realistic system with separated optical and mechanical degrees of freedom, in which a high-mechanical-quality silicon nitride membrane is placed upon a high-optical-quality whispering gallery microcavity. The strongly enhanced linear optomechanical coupling, together with simultaneously low optical and mechanical losses in the present system, results in a remarkable single-photon cooperativity exceeding 300. This unprecedented cooperativity in the optomechanical system enables optical nonlinearity at low light intensities and holds great potential in generating, storing, and implementing quantum states. Moreover, the device gives rise to significantly stronger quadratic optomechanical coupling than achieved to date, which is desirable for measuring phonon shot noise with a high signal-to-noise ratio.