Determination of polariton condensates' critical temperature

TL;DR

This study measures the critical temperature at which polariton condensates lose coherence, using time-resolved photoluminescence to analyze their thermal robustness and compare experimental results with atomic BEC models.

Contribution

First experimental determination of the critical temperature for polariton condensates and comparison with atomic BEC theoretical models.

Findings

Critical temperature identified for polariton condensates.

Gradual decay of condensate coherence with temperature.

Experimental results compared with atomic BEC models.

Abstract

We investigate the thermal robustness of traveling polariton condensates. We create remote condensates that have never been in contact, and study their interference in momentum space, when they travel with the same velocity, by means of time-resolved photoluminescence. We determine the condensed to thermal, uncondensed polariton fraction, which shows a gradual decay with increasing temperature, and obtain the critical temperature for the Bose-Einstein-like condensate (BEC) phase transition. We tentatively compare our experimental findings with theoretical models, developed for atomic condensates, to describe the condensates' coherence fading with temperature.