Optomechanical trapping and cooling of partially transparent mirrors

TL;DR

This paper investigates how partially transmitting mirrors inside optical cavities can be optically trapped and cooled, revealing new regimes of interaction and proposing a bichromatic scheme for optimized cooling and trapping.

Contribution

It generalizes previous models to include partially transmitting mirrors, identifying regimes with purely dispersive coupling and proposing an optimized bichromatic cooling scheme.

Findings

Identification of regimes with purely dispersive coupling

Proposal of a bichromatic scheme for improved cooling

Qualitative differences in radiation pressure effects

Abstract

We consider the radiative trapping and cooling of a partially transmitting mirror suspended inside an optical cavity, generalizing the case of a perfectly reflecting mirror previously considered [M. Bhattacharya and P. Meystre, Phys. Rev. Lett. \textbf{99}, 073601 (2007)]. This configuration was recently used in an experiment to cool a nanometers-thick membrane [Thompson \textit{et al.}, arXiv:0707.1724v2, 2007]. The self-consistent cavity field modes of this system depend strongly on the position of the middle mirror, leading to important qualitative differences in the radiation pressure effects: in one case, the situation is similar that of a perfectly reflecting middle mirror, with only minor quantitative modifications. In addition, we also identify a range of mirror positions for which the radiation-mirror coupling becomes purely dispersive and the back-action effects that usually lead to cooling are absent, although the mirror can still be optically trapped. The existence of these two regimes leads us to propose a bichromatic scheme that optimizes the cooling and trapping of partially transmissive mirrors.