Polariton lasing at room temperature

Condensation of interacting bosons in a single macroscopic quantum phase was first theoretically pointed out by Bose and Einstein in 1924 and was experimentally demonstrated 70 years later with atoms. This delay has to be related to the low temperature (of the order of 100 nK) required for achieving atom condensation. Interestingly, cavity-polaritons in semiconductors, which are quasi-particles enabled by strong light-matter interaction, i.e. strong coupling regime (SCR) between a cavity mode and an exciton, exhibit an effective mass much lower than that of an atom by several orders of magnitude. As a consequence, Bose and Einstein condensation (BEC) of polaritons could be observed at much higher temperatures, and even room-temperature (RT).