Bose–Einstein condensation of exciton-polaritons in organic microcavities

Organic molecular materials have unique optoelectronic properties, which make them especially well suited for the study of strong matter– light coupling. Excitons — electronic excitations of such molecules — remain well defined at room temperature, and when such materials are placed in an optical cavity can couple collectively to light, with an en-ergy scale that exceeds room temperature. As such, exciton polaritons — superpositions of cavity photons and excitons — can be stable, and moreover, can reach a condensed or lasing state at room temperature. Polariton condensation refers to a state with macroscopic occupation of a single particle mode. The complex photophysics of organic moleculesrequires careful modelling to understand the optimal conditions for polariton condensation. In this article we introduce the basic physics of exciton polaritons and condensation, and review experiments demonstrating polariton condensation.