Quantum well photoelastic comb for ultra-high frequency cavity optomechanics

TL;DR

This paper introduces a quantum well photoelastic comb enabling efficient coupling at hundreds of GHz in semiconductor resonators, advancing high-frequency optomechanics for quantum tech applications.

Contribution

It presents a novel design for coupling light to ultra-high frequency mechanical modes using a photoelastic comb in semiconductor resonators, demonstrating coupling at frequencies two orders of magnitude higher than previous methods.

Findings

Spectral weight transfer from 60 GHz to 190-230 GHz modes.

Achieved coupling to mechanical frequencies two orders higher than alternatives.

Resonant photoelastic interaction enhances strong-coupling potential.

Abstract

Optomechanical devices operated at their quantum limit open novel perspectives for the ultrasensitive determination of mass and displacement, and also in the broader field of quantum technologies. The access to higher frequencies implies operation at higher temperatures and stronger immunity to environmental noise. We propose and demonstrate here a new concept of quantum well photoelastic comb for the efficient coupling of light to optomechanical resonances at hundreds of GHz in semiconductor hybrid resonators. A purposely designed ultra-high resolution Raman spectroscopy set-up is exploited to evidence the transfer of spectral weight from the mode at 60 GHz to modes at 190-230 GHz, corresponding to the $8^{th}$ and $10^{th}$ overtone of the fundamental breathing mode of the light-sound cavities. The coupling to mechanical frequencies two orders of magnitude larger than alternative approaches is attained without reduction of the optomechanical constant $g_0$. The wavelength dependence of the optomechanical coupling further proves the role of resonant photoelastic interaction, highlighting the potentiality to access strong-coupling regimes. The experimental results show that electrostrictive forces allow for the design of devices optimized to selectively couple to specific mechanical modes. Our proposal opens up exciting opportunities towards the implementation of novel approaches applicable in quantum and ultra-high frequency information technologies.