Ultraviolet lasing in resonators formed by scattering in semiconductor polycrystalline films

TLDR

The authors fabricated zinc‑oxide polycrystalline films on amorphous fused silica, where strong optical scattering creates self‑formed cavities that act as laser resonators. The study demonstrates ultraviolet lasing (~380 nm) from these self‑formed cavities under optical pumping, with microscopic images confirming the scattering‑induced resonators and indicating that such disordered microstructures can serve as alternative coherent light sources.

Abstract

A semiconductor laser whose cavities are “self-formed” due to strong optical scattering in highly disordered gain media is demonstrated. The lasers are made of zinc oxide polycrystalline films grown on amorphous fused silica substrates. Lasing occurs at an ultraviolet wavelength of ∼380 nm under optical pumping. Actual images of the microscopic laser cavities formed by multiple scattering have been captured. These results suggest the possibility of using disordered semiconductor microstructures as alternative sources of coherent light emission.