Laser phase noise effects on the dynamics of optomechanical resonators

Abstract

We investigate theoretically the influence of laser phase noise on the cooling and heating of a generic cavity optomechanical system. We derive the back-action damping and heating rates and the mechanical frequency shift of the radiation-pressure-driven oscillating mirror, and derive the minimum phonon occupation number for small laser linewidths. We find that, in practice, laser phase noise does not pose serious limitations to ground-state cooling. Additionally, we explore the regime of parametric amplification where coherent oscillations of the mirror are realizable. It is found that heating from laser phase noise is of significance and can cause the onset of instabilities. We then consider the effects of laser phase noise in a parametric cavity driving scheme that minimizes the back-action heating of one of the quadratures of the mechanical oscillator motion. Laser linewidths, narrow compared to the decay rate of the cavity field, do not pose any significant problems in an experimental setting, but broader linewidths limit the practicality of this back-action evasion method.