Miniature GaAs disk resonators probed by a looped fiber taper for optomechanics applications

TL;DR

This paper demonstrates the optomechanical characterization of GaAs disk resonators using near-field optical coupling, revealing high-Q whispering gallery modes and a natural coupling between optical and mechanical degrees of freedom at the micro-nanoscale.

Contribution

The study introduces a method for probing GaAs disk resonators with a looped fiber taper, highlighting their potential for enhanced optomechanical interactions.

Findings

Optical Q factors up to a few 10^5 observed.

Critical coupling and mode splitting analyzed.

Optical force attraction demonstrates coupling of optical and mechanical modes.

Abstract

GaAs disk resonators (typical disk size 5 \mum * 200 nm in our work) are good candidates for boosting optomechanical coupling thanks to their ability to confine both optical and mechanical energy in a sub-micron interaction volume. We present results of optomechanical characterization of GaAs disks by near-field optical coupling from a tapered silica nano-waveguide. Whispering gallery modes with optical Q factor up to a few 10^5 are observed. Critical coupling, optical resonance doublet splitting and mode identification are discussed. We eventually show an optomechanical phenomenon of optical force attraction of the silica taper to the disk. This phenomenon shows that mechanical and optical degrees of freedom naturally couple at the micro-nanoscale.