ZnO-based random lasing on nanoparticles realized by laser induced breakdown

A simple laser-assisted method to transform metallic Zn to a ZnO-based random lasing medium is reported. The method uses Nd+3 laser-induced air breakdown to treat the surface of a Zn target and thus produce ZnO nanoparticles randomly scattered over the broken area. Photoluminescence spectra of some places of the area at room temperature under resonant powerful photoexcitation exhibit the emission band at 395 nm with regularly spacing narrow spikes (<1 nm), which is typical of multi-mode lasing. The band is suggested to be originated from electron-hole plasma arising at high excitation in ZnO-based structures. The micro lasers revealed are possibly composed of ZnO nanoparticles scattered in chains inside self-made random resonators, with Zn flinders being mirrors.