Fig. 6

a–c Intrinsic cavities of MHPs. a Perovskite crystals with different morphologies, including 1D (i) nanowires, 2D (ii) triangular, (iii) tetragonal, (iv) hexagonal, and (v) octagonal microdisks, and 3D (vi) microspheres. b Optical trajectories and c The corresponding simulated field distribution of perovskite cavities with different morphologies [72]. d–g Extrinsic cavities of MHPs, d side-view SEM image of a microsphere cavity [74]. e Schematic diagrams of capillary cavity with circular WGM laser resonances [75]. f SEM image of DFB laser on a quartz substrate [76]. g Cross-sectional SEM image of a perovskite DBR laser device [77]