Frequency-Upconversion Single-Mode Lasing in CsPbBr₃ Nanowires at Room Temperature

Frequency upconversion provides a feasible strategy for switching the resonant wavelength of lasing modes. However, this nonlinear process requires extremely high optical properties for the medium. Here, the high-quality CsPbBr 3 nanowires were prepared by using the antisolvent method, which can serve as both the optical gain medium and resonant cavity. The highly polarized single-photon lasing was achieved with a low threshold of 6.69 μJ/cm 2, excited by a 390 nm femtosecond pulse laser. Furthermore, frequency-upconversion single-mode lasing output was successfully operated at room temperature in a single CsPbBr 3 nanowire with a length of 3.5 μm under pumping of an 800 nm femtosecond pulse laser. These findings suggest that the prepared all-inorganic perovskite nanowires can be used as excellent optical gain media for frequency-upconversion lasers, providing a versatile platform for constructing nonlinear optoelectronic devices, such as optical switches, optical limiters, and biomedical imaging.