Tunable vertical cavity microlasers based on MAPbI<sub>3</sub> phase change perovskite

Perovskite semiconductors show great promise as gain media for all-solution-processed single-mode microlasers. However, despite the recent efforts to improve their lasing performance, achieving tunable single-mode microlasers remains challenging. In this work, we address this challenge by demonstrating a tunable vertical cavity surface emitting laser (VCSEL) employing a tunable gain medium of halide phase-change perovskites-specifically MAPbI₃ perovskite, sandwiched between two highly reflective mirrors composed of bottom-distributed Bragg reflectors (DBRs). This VCSEL possesses single-mode lasing emission with a low threshold of 23.5 μJ cm⁻² under 160 K, attributed to strong optical confinement in the high-quality (<italic>Q</italic>) cavity. Upon the phase change of MAPbI₃ perovskite, both its gain and dielectric constant changes dramatically, enabling a wide (Δ<italic>λ</italic> &gt;9 nm) and temperature-sensitive (0.30 nm K⁻¹ rate) spectral tunability of lasing mode in the near-infrared (N-IR) region. The laser displays excellent stability, demonstrating an 80% lifetime of &gt;2.4×10⁷ pulses excitation. Our findings may provide a versatile platform for the next generation of tunable coherent light sources.