Enhanced photon-phonon coupling via dimerization in one-dimensional optomechanical crystals

TL;DR

This paper demonstrates that dimerization in one-dimensional optomechanical crystals enhances photon-phonon coupling, with experimental validation showing a significant increase in vacuum coupling rate in a silicon nanobeam cavity.

Contribution

The study introduces a dimerized lattice design that improves photon-phonon interaction in optomechanical crystals, supported by experimental measurements.

Findings

Enhanced photon-phonon coupling via dimerization.

Experimental vacuum coupling rate of 1.7 MHz achieved.

Dimerization leads to band folding and mode coupling.

Abstract

We show that dimerization of an optomechanical crystal lattice, which leads to folding of the band diagram, can couple flexural mechanical modes to optical fields within the unit cell via radiation pressure. When compared to currently realized crystals, a substantial improvement in the coupling between photons and phonons is found. For experimental verification, we implement a dimerized lattice in a silicon optomechanical nanobeam cavity and measure a vacuum coupling rate of $g_0/2\pi=1.7MHz$ between an optical resonance at $\lambda_{c} = 1545nm$ and a mechanical resonance at 1.14GHz.