Enhancement of ultraviolet lasing from Ag-coated highly disordered ZnO films by surface-plasmon resonance

Abstract

Large improvement in random lasing action at ultraviolet wavelength has been achieved from highly disordered ZnO films with Ag coating. The lasing threshold can be reduced by two times and slope efficiency can be increased by 5.5 times. The improvement is due to the presence of Ag coating, which enhances the surface coupling of lasing emission from the ZnO films by surface-plasmon resonance and reduces the scattering loss experienced by the random cavity modes. Furthermore, the enhancement of lasing efficiency is dependent on the Ag coating’s surface roughness, which can be controlled through the surface morphology of ZnO films.