Two-photon pumped random lasing in MAPbBr3 with directional output for far-field applications.

We investigate the random lasing properties of polycrystalline MAPbBr 3 grown in a hollow fiber. Coupling of the random lasing on the inner wall of the hollow fiber into the annular cylinder and guided by the inner surface of hollow cavity enable directional output of the random lasing emission. The polycrystalline MAPbBr 3 was grown by the capillary effect, when one end of the hollow fiber was dipped into the precursor solution. A two-photon pumping scheme was employed, where femtosecond pulses centered at about 800 nm was focused onto the MAPbBr 3 polycrystals through the side wall of the hollow fiber. Random lasing was achieved due to the strong optical scattering by the interfaces within the polycrystals on the inner wall of the hollow fiber. The random lasing output was re-collimated into a roughly parallel beam with a circular transverse mode, which favors far-field applications of random lasers. Two-photon pumping enables larger penetration depth and larger excitation volume than single-photon pumping, so that strong lasing spot can also be observed in the center area of the output laser beam. • Growth of polycrystalline layer of MAPbBr 3 on the inner wall of a hollow fiber with optimized precursor solution for the fabrication of a random laser device. • Recollimated laser beam was achieved for the random lasing emission inside a hollow fiber, where spatial confinement and direction guiding by the hollow fiber are the responsible mechanisms. • Random lasing beam with a small divergence and regular transverse mode is very important for the practical far-field applications. • Two-photon pumping scheme was employed for such a random laser device, where large thickness of the active medium allows large penetration depth of the pump laser. [ABSTRACT FROM AUTHOR]