Laser and cavity cooling of a mechanical resonator with a Nitrogen-Vacancy center in diamond

TL;DR

This paper presents a theoretical analysis of cooling a mechanical resonator coupled with a nitrogen-vacancy (NV) center in diamond, exploring how cavity and laser interactions influence cooling efficiency and regimes.

Contribution

It derives a rate equation for the mechanical motion considering NV center interactions, and investigates how cavity presence and dephasing affect cooling performance.

Findings

Cavity addition generally does not improve cooling efficiency.

Pure dephasing can enhance cooling performance.

Optimal cooling achieved with specific electronic transition linewidths.

Abstract

We theoretically analyse the cooling dynamics of a high-Q mode of a mechanical resonator, when the structure is also an optical cavity and is coupled with a NV center. The NV center is driven by a laser and interacts with the cavity photon field and with the strain field of the mechanical oscillator, while radiation pressure couples mechanical resonator and cavity field. Starting from the full master equation we derive the rate equation for the mechanical resonator's motion, whose coefficients depend on the system parameters and on the noise sources. We then determine the cooling regime, the cooling rate, the asymptotic temperatures, and the spectrum of resonance fluorescence for experimentally relevant parameter regimes. For these parameters, we consider an electronic transition, whose linewidth allows one to perform sideband cooling, and show that the addition of an optical cavity in general does not improve the cooling efficiency. We further show that pure dephasing of the NV center's electronic transitions can lead to an improvement of the cooling efficiency.