Tutorial: Opto-mechanical cooling by the back-action of cavity photons

TL;DR

This paper analyzes how light interacting with a Fabry-Perot cavity can be used for opto-mechanical cooling, highlighting the role of photon lifetime and detuning in damping mirror vibrations.

Contribution

It provides a classical analysis of opto-mechanical cooling mechanisms involving cavity photon back-action and sideband effects.

Findings

Sideband symmetry in adiabatic approximation

Photon lifetime affects sideband symmetry

Proper detuning enables cooling or amplification

Abstract

We present a simple classical analysis of light interacting with a Fabry-Perot cavity consisting of a fixed (dielectric) front mirror and a vibrating rear mirror. In the adiabatic approximation, the returning light exhibits sideband symmetry, which will go away once the photon lifetime becomes comparable to or longer than the oscillation period of the rear mirror. When the oscillation period is short compared to the cavity photon lifetime, one must approach the problem differently, treating the vibrating mirror as a scatterer which sends a fraction of the incident light into sideband frequencies. With proper detuning, the cavity's internal radiation pressure could either dampen or amplify the vibrations of the mirror; the former is the physical principle behind opto-mechanical cooling by the back-action of cavity photons.