Polariton condensates at room temperature

TL;DR

This review discusses recent advances in room-temperature polariton condensates in microcavities, highlighting material systems, condensation mechanisms, and potential device applications, enabling detailed thermodynamic and dynamical studies.

Contribution

It provides a comprehensive comparison of different material systems and their figures of merit for room-temperature polariton condensation, and discusses the dynamics and mechanisms involved.

Findings

Demonstration of polariton lasing at room temperature

Comparison of various material systems for polariton condensation

Insights into the condensation mechanisms and dynamics

Abstract

We review the recent developments of the polariton physics in microcavities featuring the exciton-photon strong coupling at room-temperature, and leading to the achievement of room-temperature polariton condensates. Such cavities embed active layers with robust excitons that present a large binding energy and a large oscillator strength, i.e. wide bandgap inorganic or organic semiconductors, or organic molecules. These various systems are compared, in terms of figures of merit and of common features related to their strong oscillator strength. The various demonstrations of polariton laser are compared, as well as their condensation phase diagrams. The room-temperature operation indeed allows a detailed investigation of the thermodynamic and out-of-equilibrium regimes of the condensation process. The crucial role of the spatial dynamics of the condensate formation is discussed, as well as the debated issue of the mechanism of stimulated relaxation from the reservoir to the condensate under non-resonant excitation. Finally the prospects of polariton devices are presented.