Pseudorandom lasing emission from self-patterned thin films of CsPbBr3

Metal halide perovskites have garnered considerable interest for their potential uses in high-efficiency photonics, particularly in the construction of on-chip lasers. Despite extensive efforts to understand the mechanisms underlying perovskite-based lasing, no clear consensus has emerged. Moreover, the fabrication of practical lasing emitters requires the challenging integration of a low-defect active material into a device architecture with minimized complexity. In this study, we demonstrate a simple, multimode lasing emitter composed of a millimeter-scale single-crystalline thin film of CsPbBr3. Dislocations, created during vapor-based film deposition, function as lasing cavity walls and form close-packed sets of resonators with random sizes at two orthogonal orientations within the thin film. Collecting ensemble temperature and power-dependent lasing characteristics of multiple, independent lasing modes in a single sample enables a statistical analysis of the underlying lasing mechanism. Our results reveal that the power-dependent red-shift in the stimulated emission envelope is caused by coupling between the radiatively recombining excitons and the collective oscillations of a photoexcited electron-hole plasma within the perovskite.