Spatial and temporal dynamics of the crossover from exciton–polariton condensation to photon lasing

At a sufficiently high density, the bosonic exciton–polariton system breaks down and the constituent electron, hole, and photon nature is revealed. Although conventional photon lasing is expected in this regime, the nature of the crossover from polariton condensation to photon lasing is not yet well understood. Through detailed mapping, we deconvolute the spatial, temporal, momentum, and energy dependences of the photoluminescence from this system at the crossover point. Photon lasing is distinctly observed far above this crossover.