Optomechanical Multi-Mode Hamiltonian for Nanophotonic Waveguides

TL;DR

This paper presents a systematic method to derive a quantum multi-mode Hamiltonian for photon-phonon interactions in nanophotonic waveguides, accurately modeling Brillouin scattering phenomena.

Contribution

It introduces a unified perturbation theory approach to derive the Hamiltonian, including both radiation pressure and electrostrictive effects, applied specifically to nanoscale waveguides.

Findings

Radiation pressure dominates electrostriction in nanoscale waveguides.

Derived coupling parameters match experimental Brillouin gain measurements.

Analytical model agrees with recent experimental observations.

Abstract

We develop a systematic method for deriving a quantum optical multi-mode Hamiltonian for the interaction of photons and phonons in nanophotonic dielectric materials by applying perturbation theory to the electromagnetic Hamiltonian. The Hamiltonian covers radiation pressure and electrostrictive interactions on equal footing. As a paradigmatic example, we apply our method to a cylindrical nanoscale waveguide, and derive a Hamiltonian description of Brillouin quantum optomechanics. We show analytically that in nanoscale waveguides radiation pressure dominates over electrostriction, in agreement with recent experiments. The calculated photon-phonon coupling parameters are used to infer gain parameters of Stokes Brillouin scattering in good agreement with experimental observations.