Opt Lett. 2022 Nov 1;47(21):5481-5484. doi: 10.1364/OL.465567.
A typical optomechanical system is a cavity with one movable mirror and one fixed mirror. However, this configuration has been considered incapable of integrating sensitive mechanical elements while maintaining high cavity finesse. Although the membrane-in-the-middle solution seems to be able to overcome this contradiction, it introduces additional components that will lead to unexpected insertion loss, resulting in reduced cavity quality. Here we propose a Fabry-Perot optomechanical cavity composed of an ultrathin suspended SiN metasurface and a fixed Bragg grating mirror, with a measured finesse up to 1100. Transmission loss of this cavity is very low as the reflectivity of this suspended metasurface tends to unity around 1550 nm. Meanwhile, the metasurface has a millimeter-scale transverse dimension and a thickness of only 110 nm, which guarantees a sensitive mechanical response and low cavity diffraction loss. Our metasurface-based high-finesse optomechanical cavity has a compact structure, which facilitates the development of quantum and integrated optomechanical devices.
典型的光机械系统是一个带有一个可动反射镜和一个固定反射镜的腔。然而，这种配置被认为无法在保持高腔精细度的同时集成敏感的机械元件。虽然中间膜的解决方案似乎能够克服这一矛盾，但它引入了额外的组件，这将导致意想不到的插入损耗，从而降低腔的质量。在这里，我们提出了一种由超薄膜状氮化硅超构表面和固定布拉格光栅反射镜组成的法布里-珀罗光机械腔，其测量的精细度高达 1100。由于该悬浮超构表面在 1550nm 左右的反射率趋于 1，因此该腔的传输损耗非常低。同时，该超构表面的横向尺寸为毫米级，厚度仅为 110nm，这保证了灵敏的机械响应和低的腔衍射损耗。我们基于超构表面的高光机械精细度光机械腔具有紧凑的结构，有利于量子和集成光机械器件的发展。
