Ground-state cooling of dispersively coupled optomechanical system in unresolved sideband regime via dissipatively coupled oscillator

TL;DR

This paper demonstrates a method to cool a dispersively coupled optomechanical oscillator to its ground state in the unresolved sideband regime by using an ancillary dissipatively coupled oscillator and a single blue-detuned laser.

Contribution

It introduces a novel cooling scheme employing an ancillary oscillator with dissipative coupling to achieve ground-state cooling outside the resolved sideband regime.

Findings

Ground-state cooling achieved in unresolved sideband regime

Uses dissipative coupling with an ancillary oscillator

Requires only a single blue-detuned laser

Abstract

In the optomechanical cooling of a dispersively coupled oscillator, it is only possible to reach the oscillator ground state in the resolved sideband regime, where the cavity-mode line width is smaller than the resonant frequency of the mechanical oscillator being cooled. In this paper, we show that the dispersively coupled system can be cooled to the ground state in the unresolved sideband regime using an ancillary oscillator, which is coupled to the same optical mode via dissipative interaction. The ancillary oscillator has a resonant frequency close to that of the target oscillator; thus, the ancillary oscillator is also in the unresolved sideband regime. We require only a single blue-detuned laser mode to drive the cavity.