QED description of Raman scattering from molecules in plasmonic cavities

TL;DR

This paper develops a quantum electrodynamics framework to describe Raman scattering in molecules within plasmonic cavities, revealing nonlinear effects and novel phenomena like phonon-stimulated Raman scattering.

Contribution

It introduces a quantum electrodynamics approach to analyze nonlinear Raman effects and photon correlations in plasmonic systems, surpassing classical models.

Findings

Prediction of phonon-stimulated Raman scattering

Counter-intuitive dependence of anti-Stokes emission on excitation frequency

Analysis of photon emission correlations in plasmonic cavities

Abstract

Plasmon-enhanced Raman scattering can push single-molecule vibrational spectroscopy beyond a regime addressable by classical electrodynamics. We employ a quantum electrodynamics (QED) description of the coherent interaction of plasmons and molecular vibrations that reveal the emergence of nonlinearities in the inelastic response of the system. For realistic situations, we predict the onset of \textit{phonon-stimulated Raman scattering} and an counter-intuitive dependence of the anti-Stokes emission on the frequency of excitation. We further show that this novel QED framework opens a venue to analyze the correlations of photons emitted at a plasmonic cavity