  Atomically thin transition metal dichalcogenides possess valley dependent
functionalities that are usually available only at crogenic temperatures,
constrained by various valley depolarization scatterings. The formation of
exciton polaritons by coherently superimposing excitons and microcavity photons
potentially harnesses the valley polarized polariton polariton interactions for
novel valleytronics devices. Robust EPs have been demonstrated at room
temperature in TMDs microcavity, however, the coherent polariton lasing and
condensation remain elusive. Herein, we demonstrate for the first time the
realization of EP condensation in a TMD microcavity at room temperature. The
continuous wave pumped EP condensation and lasing with ultralow thresholdsis
evidenced by the macroscopic occupation of the ground state, that undergoes a
nonlinear increase of the emission and a continuous blueshift, a build up of
spatial coherence, and a detuning-controlled threshold. Our work presents a
critically important step towards exploiting nonlinear polariton polariton
interactions and polaritonic devices with valley functionality at room
temperature.
