Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
DTU Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Ørsteds Plads 343, Kgs. Lyngby, DK-2800, Denmark.
Phys Rev Lett. 2023 Jan 27;130(4):043802. doi: 10.1103/PhysRevLett.130.043802.
Confining photons in cavities enhances the interaction between light and matter. In cavity optomechanics, this enables a wealth of phenomena ranging from optomechanically induced transparency to macroscopic objects cooled to their motional ground state. Previous work in cavity optomechanics employed devices where ubiquitous structural disorder played no role beyond perturbing resonance frequencies and quality factors. More generally, the interplay between disorder, which must be described by statistical physics, and optomechanical effects has thus far been unexplored. Here, we demonstrate how sidewall roughness in air-slot photonic-crystal waveguides can induce sufficiently strong backscattering of slot-guided light to create Anderson-localized modes with quality factors as high as half a million and mode volumes estimated to be below the diffraction limit. We observe how the interaction between these disorder-induced optical modes and in-plane mechanical modes of the slotted membrane is governed by a distribution of coupling rates, which can exceed g_{o}/2π∼200 kHz, leading to mechanical amplification up to self sustained oscillations via optomechanical backaction. Our Letter constitutes the first steps towards understanding optomechanics in the multiple-scattering regime and opens new perspectives for exploring complex systems with a multitude of mutually coupled degrees of freedom.
将光子限制在腔体内可以增强光与物质之间的相互作用。在腔光机械学中，这使得一系列现象成为可能，从光机械诱导透明到宏观物体冷却到它们的运动基态。以前的腔光机械学工作采用的设备中，无处不在的结构无序除了扰乱共振频率和品质因数外，没有发挥其他作用。更一般地说，无序与光机械效应之间的相互作用，迄今为止尚未得到探索，而无序必须用统计物理来描述。在这里，我们展示了空气槽光子晶体波导的侧壁粗糙度如何能引起槽导光的强反向散射，从而产生具有高达 50 万的高品质因数和估计低于衍射极限的模式体积的安德森局域模式。我们观察到这些无序诱导的光学模式与开槽膜的面内机械模式之间的相互作用是由耦合速率的分布来控制的，这种分布可以超过 g_{o}/2π∼200 kHz，通过光机械反馈导致机械放大，直至自持续振荡。我们的信构成了理解多散射 regime 中的光机械学的第一步，并为探索具有多个相互耦合自由度的复杂系统开辟了新的视角。
