Ultralow Threshold Polariton Condensate in a Monolayer Semiconductor Microcavity at Room Temperature

Exciton-polaritons, hybrid light-matter bosonic quasiparticles, can condense into a single quantum state, i.e., forming a polariton Bose-Einstein condensate (BEC), which represents a crucial step for the development of nanophotonic technology. Recently, atomically thin transition-metal dichalcogenides (TMDs) emerged as promising candidates for novel polaritonic devices. Although the formation of robust valley-polaritons has been realized up to room temperature, the demonstration of polariton lasing remains elusive. Herein, we report for the first time the realization of this important milestone in a TMD microcavity at room temperature. Continuous wave pumped polariton lasing is evidenced by the macroscopic occupation of the ground state, which undergoes a nonlinear increase of the emission along with the emergence of temporal coherence, the presence of an exciton fraction-controlled threshold and the buildup of linear polarization. Our work presents a critically important step toward exploiting nonlinear polariton-polariton interactions, as well as offering a new platform for thresholdless lasing.

Automated summary

This study reports the realization of polariton lasing in a TMD microcavity at room temperature for the first time, showing evidence of continuous wave pumped polariton lasing through macroscopic occupation of the ground state, emergence of temporal coherence, presence of an exciton fraction-controlled threshold, and buildup of linear polarization. This work represents a critical step towards utilizing nonlinear polariton-polariton interactions and providing a new platform for thresholdless lasing.