Two-dimensional spectral-spatial analysis of ZNO nanoparticles random lasers

We introduce a two dimensional model to analyze zinc oxide (ZnO) random lasers. Medium is made up of ZnO nanoparticles distributed randomly. Medium is pumped with an optical pulse. The results reveal that when pump intensity is under threshold, output emission is dominated by spontaneous emission with low intensity. When pump intensity increases above the threshold, stimulated emission starts forming, so lasing modes appear in the output spectra. Hence the output intensity increases rapidly. Spatial analysis of the medium shows when pump intensity is under threshold, optical closed loops cannot be seen, while closed optical loops due to multiple scattering of light occur when pump intensity increases above the threshold. Investigation about emission spectra from different arbitrary locations of the specific structure Shows that each location has its own spectrum pattern and frequency modes.