High frequency GaAs nano-optomechanical disk resonator

TL;DR

This paper demonstrates a GaAs nano-optomechanical disk resonator with ultra-strong coupling, high sensitivity, and mechanical modes in a sub-micron volume, advancing room-temperature quantum-limited measurements.

Contribution

It introduces a GaAs disk resonator with record optomechanical coupling rates and high sensitivity, enabling new possibilities in quantum optomechanics.

Findings

Optomechanical coupling rate up to 100 GHz/nm

Mechanical modes with frequencies between 100 MHz and 1 GHz

Optical detection sensitivity approaching quantum limit

Abstract

Optomechanical coupling between a mechanical oscillator and light trapped in a cavity increases when the coupling takes place in a reduced volume. Here we demonstrate a GaAs semiconductor optomechanical disk system where both optical and mechanical energy can be confined in a sub-micron scale interaction volume. We observe giant optomechanical coupling rate up to 100 GHz/nm involving picogram mass mechanical modes with frequency between 100 MHz and 1 GHz. The mechanical modes are singled-out measuring their dispersion as a function of disk geometry. Their Brownian motion is optically resolved with a sensitivity of 10^(-17)m/sqrt(Hz) at room temperature and pressure, approaching the quantum limit imprecision.