Forced and self-excited oscillations of an optomechanical cavity

TL;DR

This paper experimentally investigates forced and self-induced oscillations in an optomechanical cavity, revealing how optical power influences mechanical resonance and damping, with heating effects playing a key role.

Contribution

It provides new experimental insights into optomechanical interactions involving a fiber Bragg grating and metallic resonator, highlighting the heating mechanism as dominant.

Findings

Optomechanical coupling affects resonance frequency and damping.

Self oscillations occur above a specific optical power threshold.

Heating due to optical absorption is the main coupling mechanism.

Abstract

We experimentally study forced and self oscillations of an optomechanical cavity which is formed between a fiber Bragg grating that serves as a static mirror and between a freely suspended metallic mechanical resonator that serves as a moving mirror. In the domain of small amplitude mechanical oscillations, we find that the optomechanical coupling is manifested as changes in the effective resonance frequency, damping rate and cubic nonlinearity of the mechanical resonator. Moreover, self oscillations of the micromechanical mirror are observed above a certain optical power threshold. A comparison between the experimental results and a theoretical model that we have recently presented yields a good agreement. The comparison also indicates that the dominant optomechanical coupling mechanism is the heating of the metallic mirror due to optical absorption.