Coherent electron-vibron interactions in Surface-Enhanced Raman Scattering (SERS)

TL;DR

This paper develops a quantum model revealing how coherent electron-vibron interactions in SERS can significantly modify spectral peaks and generate nonclassical photon correlations, surpassing traditional optomechanical explanations.

Contribution

It introduces a first-principles open-system quantum model for SERS that accounts for coherent electron-vibron interactions beyond standard optomechanical theories.

Findings

Raman peak modifications by several orders of magnitude.

Generation of nonclassical photon pair correlations.

Significant impact on quantum estimations of SERS spectra.

Abstract

In this work we identify coherent electron-vibron interactions between near-resonant and non-resonant electronic levels that contribute beyond standard optomechanical models for off-resonant or resonance SERS. By developing an open-system quantum model using first molecular interaction principles, we show how the Raman interference of both resonant and non-resonant contributions can provide several orders of magnitude modifications of the SERS peaks with respect to former optomechanical models and over the fluorescence backgrounds. This cooperative optomechanical mechanism allows for generating an enhancement of nonclassical photon pair correlations between Stokes and anti-Stokes photons, which can be detected by photon-counting measurements. Our results demonstrate Raman enhancements and suppressions of coherent nature that significantly impact the standard estimations of the optomechanical contribution from SERS spectra and their quantum mechanical observable effects.