Optimized optomechanical crystal cavity with acoustic radiation shield

TL;DR

This paper designs an optimized optomechanical crystal nanobeam cavity using simulation and optimization, achieving high optical and mechanical Q-factors, a GHz mechanical frequency, and strong optomechanical coupling.

Contribution

It introduces a novel design methodology combining finite-element simulation with numerical optimization for optomechanical crystals.

Findings

Optical Q-factor of 1.2 million achieved.

Mechanical frequency of 5.1 GHz demonstrated.

Mechanical Q-factor of 6.8x10^5 at 10K obtained.

Abstract

We present the design of an optomechanical crystal nanobeam cavity that combines finite-element simulation with numerical optimization, and considers the optomechanical coupling arising from both moving dielectric boundaries and the photo-elastic effect. Applying this methodology results in a nanobeam with an experimentally realized intrinsic optical Q-factor of 1.2x10^6, a mechanical frequency of 5.1GHz, a mechanical Q-factor of 6.8x10^5 (at T=10K), and a zero-point-motion optomechanical coupling rate of g=1.1MHz.