Nontoxic metal-halide perovskite materials have triggered a revolution of emitting devices as well as solar cells. In this work, we demonstrate a lead-free γ-CsSnI 3 perovskite random lasing operated at room temperature in ambient air. The high-purity γ-CsSnI 3 films with the orthorhombic structure were grown by chemical vapor deposition (CVD). From the absorption and photoluminescence (PL) spectra, the intense PL emission at 950 nm is consistent with the γ-CsSnI 3 band-edge absorption. Moreover, the PL stability test shows the prolonged stability of CVD-grown films. With increasing excitation energy above 18 mJ/cm 2 , the random laser with a high Q-factor (∼3000) is achieved.

This work demonstrates the electrical tuning of laser beam shape using an axially symmetric dye-dope liquid crystal (ASDDLC) device that is fabricated using a photo-alignment method. Various beam shapes can be obtained by linearly polarized Gaussian laser beams through an ASDDLC device under various applied voltages. The far-field intensity patterns generated by laser beams of selected shapes under various applied voltages are simulated, and the results are consistent with experiment. A rotatable petal-shaped beam is obtained by controlling the polarization of the output donut-shaped beam. The tenability of beam shape of light with a wavelength of 1064 nm, which is commonly used in biomedical applications, is also demonstrated.