Phase-noise induced limitations on cooling and coherent evolution in opto-mechanical systems

TL;DR

This paper analyzes how laser phase noise impacts cooling and coherent dynamics in opto-mechanical systems, showing that while it introduces limitations, ground state cooling and coherent operations remain feasible.

Contribution

It provides a detailed theoretical evaluation of laser phase noise effects on opto-mechanical cooling and coherent transfer, highlighting the dominant heating mechanisms and practical feasibility.

Findings

Laser intensity fluctuations dominate heating at small linewidths.

Final occupation number scales linearly with cavity intensity.

Ground state cooling remains feasible despite phase noise.

Abstract

We present a detailed theoretical discussion of the effects of ubiquitous laser noise on cooling and the coherent dynamics in opto-mechanical systems. Phase fluctuations of the driving laser induce modulations of the linearized opto-mechanical coupling as well as a fluctuating force on the mirror due to variations of the mean cavity intensity. We first evaluate the influence of both effects on cavity cooling and find that for a small laser linewidth the dominant heating mechanism arises from intensity fluctuations. The resulting limit on the final occupation number scales linearly with the cavity intensity both under weak and strong coupling conditions. For the strong coupling regime, we also determine the effect of phase noise on the coherent transfer of single excitations between the cavity and the mechanical resonator and obtain a similar conclusion. Our results show that conditions for optical ground state cooling and coherent operations are experimentally feasible and thus laser phase noise does pose a challenge but not a stringent limitation for opto-mechanical systems.