Interplay between tightly focused excitation and ballistic propagation of polariton condensates in a ZnO microcavity

TL;DR

This study explores how tightly focused excitation influences the formation and ballistic propagation of polariton condensates in a ZnO microcavity, combining experimental imaging with theoretical modeling to identify key parameters affecting condensation.

Contribution

It provides a combined experimental and theoretical analysis of polariton condensate behavior under focused excitation, linking small-spot experiments with kinetic models and identifying critical parameters.

Findings

Identification of exciton-photon detuning as a key parameter

Determination of temperature's role in relaxation efficiency

Correlation between experimental profiles and Gross-Pitaevskii model

Abstract

The formation and propagation of a polariton condensate under tightly focused excitation is investigated in a ZnO microcavity both experimentally and theoretically. 2D near-field and far-field images of the condensate are measured under quasi-continuous non-resonant excitation. The corresponding spatial profiles are compared to a model based on the Gross-Pitaevskii equation under cylindrical geometry. This work allows to connect the experiments performed with a small excitation laser spot and the previous kinetic models of condensation in a 2D infinite microcavity, and to determine the relevant parameters of both the interaction and the relaxation between the reservoir and the condensate. Two main parameters are identified: the exciton-photon detuning through the polariton effective mass and the temperature, which determines the efficiency of the relaxation from the reservoir to the condensate.