Halide perovskites are a promising optical gain media for lasers. In this work, the phenomenon of random lasing is studied in the halide perovskite MAPbI3 single crystal at a temperature of 4 K and pico- or femtosecond pulsed optical pumping. Spectral, temporal, polarimetric, and threshold measurements facilitate isolating random lasing from the photoluminescence background. Spectral localization of the lasing lines points to defect-related states emission as the lasing origin. Time-resolved photoluminescence study shows that the random lasing is emitted as an ultrashort pulse with a duration below 10 ps, and the photoluminescence background as a long 100 ps afterglow. The mechanism of lasing in MAPbI3 halide perovskite is determined, which is ultrafast radiation from states associated with defects. The obtained information will make it possible to increase the efficiency of lasing in halide perovskites by controlled introduction of radiating states in the material transparency region.

Resonant diffractive optical elements can be used to create the desired spatial and angular distribution of scattered light in a narrow wavelength range. Exciton resonance could help to make such elements active. Here an exciton diffraction grating made from fully inorganic CsPbBr3 halide perovskite is demonstrated. Spatial modulation of excitonic properties of the single crystal is achieved using local defect formation by 30 keV Ga+ focused ion irradiation with low irradiation dose 1014 cm−2. Such a low dose prevents the appearance of non‐resonant diffraction since no sample milling occurs. The observed diffraction reflex has a maximum efficiency of 2.3 × 10−3 at the free exciton resonance and 1.7 meV spectral width. The temperature, angular, and spectral properties of resonant diffraction are studied. The possibility of creating exciton diffraction gratings based on halide perovskites is one more confirmation of their applicability as a new material for information photonics.

Halide perovskites are a promising medium for the creation of microlasers. Random lasing in single crystals can provide principal information on the nature of laser radiation in these materials. This paper demonstrates random lasing in a MAPbI3 (MA+=CH3NH_3+) single crystal at a temperature T = 30 K and pulsed optical excitation with a repetition rate of 80 MHz. The observed laser radiation has a multimode composition with a quality factor of individual modes Q ~ 1200 and threshold behavior. The paper also proposes a method for separating the background non-polarized photoluminescence and lasing signals. Keywords: halide perovskites: random lasing: MAPbI3.