Strong-coupling effects in dissipatively coupled optomechanical systems

TL;DR

This paper explores how dissipative and dispersive couplings in cavity optomechanical systems influence optical damping, frequency shifts, and strong-coupling phenomena, revealing new spectral features and transparency effects.

Contribution

It provides an exact solution for the linearized equations in dissipatively coupled systems, uncovering unique spectral signatures and conditions for amplification, cooling, and transparency.

Findings

Identification of parameter regions for amplification and cooling.

Observation of normal-mode splitting with Fano line shape.

Demonstration of optomechanically-induced transparency.

Abstract

In this paper we study cavity optomechanical systems in which the position of a mechanical oscillator modulates both the resonance frequency (dispersive coupling) and the linewidth (dissipative coupling) of a cavity mode. Using a quantum noise approach we calculate the optical damping and the optically-induced frequency shift. We find that dissipatively coupled systems feature two parameter regions providing amplification and two parameter regions providing cooling. To investigate the strong-coupling regime, we solve the linearized equations of motion exactly and calculate the mechanical and optical spectra. In addition to signatures of normal-mode splitting that are similar to the case of purely dispersive coupling, the spectra contain a striking feature that we trace back to the Fano line shape of the force spectrum. Finally, we show that purely dissipative coupling can lead to optomechanically-induced transparency which will provide an experimentally convenient way to observe normal-mode splitting.