Dispersive optomechanics of supercavity modes in high-index disks

TL;DR

This paper investigates dispersive optomechanical coupling in high-index disks, demonstrating strong coupling rates comparable to crystal cavities and proposing ultra-compact, high-frequency optomechanical metasurfaces.

Contribution

It introduces a novel dispersive coupling mechanism in wavelength-sized disks with high optomechanical coupling rates and explores methods to reduce mechanical leakage for compact device applications.

Findings

Achieved optomechanical coupling rates of about 800 kHz.

Demonstrated the possibility of coupling with mechanical modes above 10 GHz.

Showed mechanical leakage can be minimized using a silica pedestal.

Abstract

In this work, we study the dispersive coupling between optical quasi-bound-states in the continuum at telecom wavelengths and GHz-mechanical modes in high-index wavelength-sized disks. We show that such cavities can display values of the optomechanical coupling rate on par with optomechanical crystal cavities ($g_{0}/2\pi\backsimeq$ 800 kHz). Interestingly, optomechanical coupling of optical resonances with mechanical modes at frequencies well above 10 GHz seems attainable. We also show that mechanical leakage in the substrate can be extremely reduced by placing the disk over a thin silica pedestal. Our results suggest a new route for ultra compact optomechanical cavities which can potentially be arranged in massive arrays forming optomechanical metasurfaces.