Robust Quasi-Continuous-Wave Exciton–Polariton Lasing in Tin Halide Perovskite Nanowires under Ambient Conditions

Abstract Tin halide perovskites are promising lead-free optical gain media, yet stable quasi-continuous-wave/continuous-wave (quasi-CW/CW) lasing remains challenging under practical operating conditions. Here, we demonstrate robust quasi-CW lasing from single-crystalline CsSnBr3 nanowires under ambient conditions. Under quasi-CW excitation, these nanowires exhibit a low threshold of 64.5 μJ cm–2, markedly lower than that of representative III–V and II–VI semiconductor nanowires. Moreover, the CsSnBr3 nanowire lasers sustain lasing under repeated quasi-CW excitation in air for over 60 min. We further achieve wide wavelength-tunable lasing from 704 to 974 nm by Br/I alloying. In addition, we observe exciton–polariton (EP) formation and pronounced excitation-dependent blueshifts of the lasing emission, suggesting a polaritonic contribution to the low-threshold quasi-CW lasing process. These results establish tin halide perovskite nanowires as a robust, wavelength-tunable platform for quasi-CW nanolasers and support their potential for future CW nanolasers and integrated photonics.