Suppression of Random Lasing Modes in Polycrystalline ZnO Thin-Film by Using Distributed Bragg Reflector

Formation of vertical-cavity random laser by using a polycrystalline ZnO thin-film optically coupled to 11.5 pairs of Al2O3-ZnO multilayer distributed Bragg reflector (DBR) is proposed. Lasing characteristics of the laser observed from the surface of the polycrystalline ZnO thin film are studied without and with the presence of DBR. It is found that the corresponding spectral linewidth can be limited to about 4 nm at high excitation intensity under the influence of DBR.