Twisting Optomechanical Cavity

TL;DR

This paper demonstrates how torsional mechanical oscillations in an optical cavity can be coupled to optical modes via birefringence, enabling resonant driving of mechanical motion by light.

Contribution

It introduces a novel method to couple mechanical torsional oscillations with optical modes through birefringence in an optical cavity.

Findings

Torsional oscillation can be resonantly driven by light.

Birefringence creates nondegenerate optical modes in the cavity.

A torsional optomechanical Hamiltonian is derived.

Abstract

Mechanical rotation and oscillation have far lower frequencies than light does; thus they are not coupled to each other conventionally. In this Letter, we show the torsional mechanical oscillation of an optical cavity can be coupled to the optical modes by introducing birefringence, which produces nondegenerate modes in the cavity: ordinary and extraordinary rays. Twisting the cavity mixes them and modulates the electromagnetic energy. We find torsional optomechanical Hamiltonian by quantising the total energy and reveal the torsional oscillation can be resonantly driven by light.