Selectable linear or quadratic coupling in an optomechanical system

TL;DR

This paper investigates a hybrid optomechanical system with a movable cavity mirror and a dielectric sphere, revealing cross-coupling effects that enable cooling and squeezing, and proposes a method to isolate purely quadratic coupling.

Contribution

It introduces the analysis of cross-coupling effects in a system with both a movable mirror and a dielectric sphere, and suggests a way to control the coupling type.

Findings

Cross-coupling enables cooling and squeezing of the sphere.

A simple modification can eliminate cross-coupling, achieving pure quadratic coupling.

The interplay between oscillators significantly affects system dynamics.

Abstract

There has been much interest recently in the analysis of optomechanical systems incorporating dielectric nano- or microspheres inside a cavity field. We analyse here the situation when one of the mirrors of the cavity itself is also allowed to move. We reveal that the interplay between the two oscillators yields a cross-coupling that results in, e.g., appreciable cooling and squeezing of the motion of the sphere, despite its nominal quadratic coupling. We also discuss a simple modification that would allow this cross-coupling to be removed at will, thereby yielding a purely quadratic coupling for the sphere.