Coherent and incoherent aspects of polariton dynamics in semiconductor microcavities

TL;DR

This paper investigates how coherent polaritons and incoherent excitons interact in semiconductor microcavities, revealing new dephasing mechanisms and reservoir dynamics through resonant pump-probe spectroscopy and a theoretical polaritonic Bloch model.

Contribution

It introduces a simple theoretical model, the polaritonic Bloch equations, to describe the complex dynamics of polariton and exciton interactions in microcavities.

Findings

Pumping the upper polariton causes strong dephasing and long-lived reservoir formation.

Exciting the lower polariton at positive detuning also creates an efficient exciton reservoir.

A theoretical polaritonic Bloch model successfully describes the observed dynamics.

Abstract

The interaction between coherent polaritons and incoherent excitons plays an important role in polariton physics. Using resonant pump-probe spectroscopy with selective excitation of single polariton branches, we investigate the different dephasing mechanisms responsible for generating a long-lived exciton reservoir. As expected, pumping the upper polariton results in a strong dephasing process that leads to the generation of a long lived reservoir. Unexpectedly, we observe an efficient reservoir creation while exciting only the lower polariton branch when the detuning is increased towards positive detuning. We propose a simple theoretical model, the polaritonic Bloch equations, to describe the dynamics of the system.