Deep sub-wavelength localization of light and sound in dielectric resonators

TL;DR

This paper introduces a novel dielectric bowtie design for optomechanical crystals that achieves deep sub-wavelength confinement of light and sound, leading to high coupling rates and robustness against fabrication imperfections.

Contribution

The authors propose a new dielectric bowtie unit cell design enabling deep sub-wavelength confinement and high optomechanical coupling in crystals, validated through numerical modeling and simulations.

Findings

Effective optical/mechanical mode volume of 7.6e-3 and 1.2e-3 (λ/n)³.

Single-photon optomechanical coupling rate of 2.2 MHz.

Design robustness demonstrated via Monte Carlo simulations.

Abstract

Optomechanical crystals provide coupling between phonons and photons by confining them to commensurate wavelength-scale dimensions. We present a new concept for designing optomechanical crystals capable of achieving unprecedented coupling rates by confining optical and mechanical waves to deep sub-wavelength dimensions. Our design is based on a dielectric bowtie unit cell with an effective optical/mechanical mode volume of $7.6 \times 10^{-3} {(\lambda/n_{\textrm{Si}})}^3$/$ 1.2 \times 10^{-3} {\lambda_{\textrm{mech}}}^3$. We present results from numerical modeling, indicating a single-photon optomechanical coupling of 2.2 MHz with experimentally viable parameters. Monte Carlo simulations are used to demonstrate the design's robustness against fabrication disorder.