Synthesis of Various Sized ZnO Microspheres by Laser Ablation and Their Lasing Characteristics

We have succeeded in synthesizing ZnO nano/microspheres by a simple laser ablation method in the air and demonstrated whispering-gallery-mode (WGM) lasing from the ZnO sphere excited by a pulsed-ultraviolet laser beam. The spheres with diameters of up to 10m were simply prepared by laser ablation of a ZnO sintered target by a Q-switched Nd:YAG laser in the air. In this study, we succeeded synthesizing large microspheres with diameters of larger than 20m by the Nd:YAG laser without Q-switching. The mode spacing of the large sphere was in good agreement with the WGM theory.