Millimeter-scale ultrathin suspended metasurface integrated high-finesse optomechanical cavity

Abstract

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 Si3N4 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.

A Mid-Infrared Multifunctional Optical Device Based on Fiber Integrated Metasurfaces

“…Firstly, we can deposit two layers of Si 3 N 4 on the Si substrate by chemical vapor deposition (CVD); then, we can spin coat PDMS on the Si 3 N 4 by using the transfer method to create a three-layer structure. Then, we can fabricate holes by electron-beam lithography (EBL) [30]. Next, by applying a certain adhesive to the end face of the optical fiber, transferring the metasurface structure to the end face [28], and, finally, releasing the metasurface from the SI substrate using potassium hydroxide (KOH), the structure can be successfully processed.…”

Cavity Optomechanical Bistability with an Ultrahigh Reflectivity Photonic Crystal Membrane

“…[ 9 ] In the 2D case, such “photonic crystal slabs” [ 10 ] or “PhC membranes” have found numerous applications in both optics [ 11–15 ] and optomechanics. [ 16–22 ] For cavity optomechanical applications, a key property of these devices is the reflectivity that is achieved, which determines the finesse of the optical cavity in which it is employed. Early work with 1D structures demonstrated cavities with finesse $$F = 1\,200$$ to $$F = 2\,800$$, [ 3,8 ] and subsequent “membrane‐in‐the‐middle” [ 23 ] experiments showed that even higher values of finesse were possible.…”