Energy‐Controllable Exciton‐Polariton Bose–Einstein Condensation in Perovskite Microstrip Cavities

Abstract Manipulating exciton‐polaritons (EPs) to condense into different energy states is critically important for the development of polariton‐related fundamental mechanisms and functional devices. Although various schemes are proposed for this purpose, exploiting tunable traps originating from the structure itself suffers from concomitant nonradiative recombination and dephasing effects, which limits the investigation of polariton physics and hinders their application in polaritonic devices. Here, a strategy to achieve energy‐controllable EP Bose–Einstein condensation in rationally designed low‐dimensional perovskite microcavities based on the lateral confinement and ballistic propagation of polariton condensates is demonstrated. Perovskite single‐crystal microstrips with finite lateral size provide multiple discrete polariton states. The distribution of polariton condensates among different energy states is effectively modulated by means of EP propagation in perovskite microstrips. With this new concept, stable polariton lasing with excellent wavelength‐switchability is realized. These results offer useful insight into using 1D polariton systems to construct all‐optical polaritonic circuit applications at room temperature.