High‐ Q , Low‐Threshold Monolithic Perovskite Thin‐Film Vertical‐Cavity Lasers

A vertical-cavity surface-emitting perovskite laser is achieved using a microcavity configuration where CH3 NH3 PbI3 thin solid films are embedded within a custom GaN-based high-quality (Q-factor) resonator. This single-mode perovskite laser reaches a low threshold (≈7.6 µJ cm-2 ) at room temperature and emits spatially coherent Gaussian laser beams. The devices allow direct access to the study of perovskite gain dynamics and material robustness.