Phase noise and laser-cooling limits of optomechanical oscillators

TL;DR

This paper proposes a novel optomechanical cooling scheme using two cavity modes to significantly reduce laser phase noise, enabling mechanical oscillators to reach the quantum regime, and discusses phonon number detection near this limit.

Contribution

It introduces a two-cavity-mode cooling configuration that greatly suppresses phase noise, advancing the ability to cool nano-mechanical oscillators to the quantum level.

Findings

Phase noise reduction by a factor of $(2\omega_m/\gamma)^2$

Enhanced conditions for phonon number detection near quantum regime

Potential to achieve quantum ground state cooling of mechanical oscillators

Abstract

The noise from laser phase fluctuation sets a major technical obstacle to cool the nano-mechanical oscillators to the quantum region. We propose a cooling configuration based on the opto-mechanical coupling with two cavity modes to significantly reduce this phase noise by $(2\omega_m/\gamma)^2$ times, where $\omega_m$ is the frequency of the mechanical mode and $\gamma$ is the decay rate of the cavity mode. We also discuss the detection of the phonon number when the mechanical oscillator is cooled near the quantum region and specify the required conditions for this detection.