Squeezing of the mechanical motion and beating 3 dB limit using dispersive optomechanical interactions

TL;DR

This paper demonstrates that dispersive and quadratic optomechanical couplings can be used to suppress mechanical fluctuations below the standard quantum limit, achieving squeezing beyond the 3 dB limit.

Contribution

It introduces a method to modify mechanical oscillator dynamics using quadratic coupling, enabling surpassing the 3 dB squeezing limit in optomechanical systems.

Findings

Quadratic optomechanical coupling reduces back-action effects.

Mechanical motion can be squeezed below the standard quantum limit.

The 3 dB squeezing limit can be beaten in such systems.

Abstract

We study an optomechanical system consisting of an optical cavity and movable mirror coupled through dispersive linear optomechanical coupling (LOC) and quadratic optomechanical coupling(QOC). We work in the resolved side band limit with a high quality factor mechanical oscillator in a strong coupling regime. We show that the presence of QOC in the conventional optomechanical system (with LOC alone) modifies the mechanical oscillator's frequency and reduces the back-action effects on mechanical oscillator. As a result of this the fluctuations in mechanical oscillator can be suppressed below standard quantum limit thereby squeeze the mechanical motion of resonator. We also show that either of the quadratures can be squeezed depending on the sign of the QOC. With detailed numerical calculations and analytical approximation we show that in such systems, the 3 dB limit can be beaten.