Exciton-polariton stimulated scattering in hybrid halide perovskites

TL;DR

This paper explores exciton-polariton nonlinear phenomena in hybrid halide perovskites, demonstrating stimulated scattering and ultrafast dynamics at room temperature through combined experimental and theoretical approaches.

Contribution

It presents the first detailed investigation of stimulated exciton-polariton scattering in hybrid halide perovskites under ultrafast excitation, combining experimental data with theoretical modeling.

Findings

Observation of stimulated acoustic phonon-assisted scattering above threshold fluence

Explosive growth of emission intensity and spectral narrowing

Confirmation of theoretical predictions with experimental results

Abstract

Halide perovskites, such as methylammonium lead bromide (MAPbBr$_3$), host tightly bound three-dimensional excitons which are robust at room temperature. Excellent optical properties of MAPbBr$_3$ allow for designing of optical single-mode waveguides and cavities in the frequency range close to the excitonic transitions. Taken together, this turns MAPbBr$_3$ into an excellent platform for probing exciton-polariton nonlinear phenomena at room temperature. Here we investigate ultrafast non-equilibrium dynamics of polaritons under pulsed fs non-resonant excitation. We demonstrate the presence of the stimulated acoustic phonon-assisted scattering regime above threshold pump fluence, characterized by the explosive growth of emission intensity, a redshift of the emission spectral maximum, spectral narrowing, and sub-picosecond emission dynamics. Our theoretical findings are well confirmed by the results of experimental measurements.