Photon echo in exciton-plasmon nanomaterials: a time-dependent signature of strong coupling

TL;DR

This paper explores the time-dependent photon echo signals in exciton-plasmon nanomaterials under strong coupling, revealing a double-peak spectral signature linked to hybrid polariton states, useful for ultrafast probing.

Contribution

It introduces a self-consistent Maxwell-Bloch model to simulate photon echo dynamics, highlighting a distinctive double-peak spectral feature as a signature of strong exciton-plasmon coupling.

Findings

Photon echoes depend on material parameters like molecular concentration.

A double-peak spectral signature indicates strong exciton-plasmon coupling.

The double-peak is sensitive to deviations from resonance, enabling ultrafast probing.

Abstract

We investigate the dynamics of photon echo exhibited by exciton-plasmon systems under strong coupling conditions. Using a self-consistent model based on coupled Maxwell-Bloch equations we investigate femtosecond time dynamics of ensembles of interacting molecules optically coupled to surface plasmon supporting materials. It is shown that observed photon echoes under two pulse pump-probe sequence are highly dependent on various material parameters such as molecular concentration and periodicity. Simulations of photon echoes in exciton-plasmon materials reveal a unique signature of the strong exciton-plasmon coupling, namely a double-peak structure in spectra of recorded echo signals. This phenomenon is shown to be related to hybrid states (upper and lower polaritons) in exciton-plasmon systems under strong coupling conditions. It is also demonstrated that the double-peak echo is highly sensitive to mild deviations of the coupling from resonant conditions making it a great tool for ultrafast probes.