Cavity Optomechanics with Photonic Bound States in the Continuum

TL;DR

This paper introduces a novel free-space cavity optomechanics platform using photonic crystal membranes with bound states in the continuum, enabling ultrastrong single-photon coupling and new optomechanical regimes.

Contribution

It proposes a versatile photonic crystal cavity design with bound states in the continuum, surpassing traditional devices in coupling strength and enabling advanced optomechanical experiments.

Findings

Achieves quantum cooperativity > 1 in ultrastrong coupling regime

Surpasses performance of conventional Fabry-Perot devices in non-resolved sideband regime

Enables exploration of pulsed and single-photon optomechanics

Abstract

We propose a versatile, free-space cavity optomechanics platform built from two photonic crystal membranes, one of which is freely suspended, and designed to form a microcavity less than one wavelength long. This cavity features a series of photonic bound states in the continuum that, in principle, trap light forever and can be favorably used together with evanescent coupling for realizing various types of optomechanical couplings, such as linear or quadratic coupling of either dispersive or dissipative type, by tuning the photonic crystal patterning and cavity length. Crucially, this platform allows for a quantum cooperativity exceeding unity in the ultrastrong single-photon coupling regime, surpassing the performance of conventional Fabry-Perot-based cavity optomechanical devices in the non-resolved sideband regime. This conceptually novel platform allows for exploring new regimes of the optomechanical interaction, in particular in the framework of pulsed and single-photon optomechanics.