Continuous-Wave Pumped Perovskite Lasers with Device Area Below 1 µm.

Continuous-wave (CW) pumped lasers with device areas below 1 µm constitute a key step to meeting the energy efficiency requirement for on-chip optical communications. However, a debate about whether a sub-micrometer device size and low threshold can be simultaneously satisfied has persisted owing to insurmountable radiation losses when approaching the optical diffraction limit. Herein, a record-small CW optically pumped perovskite laser with a device area of 0.65 µm is demonstrated. The thresholds of sub-micrometer lasers can be found lower than those of several-micrometer counterparts, and are ascribed to the enlarged group refractive index and modal confinement resulting from the enhanced exciton-photon coupling. Moreover, the operation temperature is elevated to 150 K through the reduction in heat generation. These findings unveil the potential of exciton-polaritons in laser miniaturization, providing an alternative for developing low-threshold semiconductor lasers without artificial optical cavities, to approach the optical diffraction limit.