Collective resonance light scattering from thermally relaxing systems in cavities

TL;DR

This study investigates steady-state resonance light scattering from molecular ensembles in cavities, revealing how spectral features evolve with system parameters and thermal relaxation effects.

Contribution

It introduces a comprehensive analysis of scattering spectra considering thermal relaxation, cavity effects, and collective molecular behaviors using two theoretical approaches.

Findings

Cavity presence causes fluorescence peak splitting into polaritonic peaks.

Spectral features scale with the number of molecules, showing collective trends.

Two theoretical methods produce qualitatively similar results, emphasizing relaxation effects.

Abstract

We study steady-state resonance light scattering from ensembles of noninteracting molecules, both in free space and inside optical cavities, while accounting for local thermal relaxation. The scattering spectra are obtained from steady-state solutions of either the Schr\"{o}dinger equation or a Liouville-space master equation. In the absence of a cavity, the spectra exhibit an elastic peak at the incident-photon energy and an inelastic fluorescence peak near the molecular excitation energy. Inside a cavity, the fluorescence peak splits into upper- and lower-polaritonic peaks in the strong-coupling regime. We analyze how the elastic and inelastic spectral features scale with the number of molecules under fixed cavity-molecule coupling and identify distinct collective trends in the Rayleigh peak intensity and in the integrated polaritonic or fluorescence spectral weight. The two theoretical approaches yield qualitatively consistent results while highlighting different aspects of thermally induced relaxation and dephasing.