Ultrafast Exciton-Polariton Transport and Relaxation in Halide Perovskite

TL;DR

This study uses advanced microscopy to directly observe ultrafast, quasi-ballistic transport and relaxation of exciton-polaritons in halide perovskites, revealing how their dynamics can be tuned for device applications.

Contribution

It introduces a high-resolution imaging method combining transient reflectance microscopy with dispersion relations to study EP transport at specific in-plane momenta.

Findings

EPs exhibit diffusion as fast as ~490 cm2/s

Relaxation time of EPs is approximately 95.1 fs

Tuning detuning parameter controls EP transport velocity and relaxation

Abstract

Halide perovskites offer a great platform for room-temperature exciton-polaritons (EPs) due to their strong oscillator strength and large exciton binding energy, promising applications in next-generation photonic and polaritonic devices. Efficient manipulation of EP transport and relaxation is critical for device performance, yet their spatiotemporal dynamics across different in-plane momenta (k//) remain poorly understood due to limitations in experimental access. In this work, we employ energy-resolved transient reflectance microscopy (TRM) combined with the dispersion relation of EPs to achieve high-resolution imaging of EP transport at specific k//. This approach directly reveals the quasi-ballistic transport and ultrafast relaxation of EPs in different k// regions, showcasing diffusion as fast as ~490 cm2/s and a relaxation time of ~95.1 fs. Furthermore, by tuning the detuning parameter, we manipulate the ballistic transport group velocity and relaxation time of EPs across varying k//. Our results reveal key insights into the dynamics of EP transport and relaxation, providing valuable guidance for the design and optimization of polaritonic devices.