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-Pérot–based cavity optomechanical devices in the nonresolved sideband regime. This platform allows for exploring new regimes of the optomechanical interaction, in particular in the framework of pulsed and single-photon optomechanics.

中文翻译：

---

具有连续光子束缚态的腔光力学

我们提出了一种多功能的，具有自由空间的腔光力学平台，该平台由两个光子晶体膜构成，其中一个膜被自由悬挂，并设计为形成长度小于一个波长的微腔。该腔具有连续的一系列光子束缚态，原则上可以永久捕获光，可以与e逝耦合一起使用，以实现各种类型的光机械耦合，例如色散或耗散类型的线性或二次耦合，通过调整光子晶体的图案和腔长。至关重要的是，该平台允许在超强单光子耦合方案中实现超过1的量子合作性，从而在非解析边带方案中超越了传统的基于Fabry-Pérot的腔体光机械设备的性能。