Numerical Simulation of Intensity Fluctuations in Random Laser Systems

Abstract

The spectral behavior of a random lasing system (TiO2 powder dispersed in Rhodamine 6 G dye solution) is calculated using numerical calculations. The total integrated intensity is calculated for different incident optical intensities, particle densities, particle size distributions. In addition to that, the power law parameters also calculated as a function of incident optical wavelength, incident optical power, number density of scatterer and size distribution of scatterer. The total integrated intensities show a sharp increase at a particular incident intensity confirming the laser action. As a signature of random lasing, the intensity at a particular wavelength varies randomly from shot to shot. This fluctuation was shown to obey power law statistics and the power law parameter was estimated for different conditions. It was seen that the power law parameter doesn’t depend on the pump intensity and emission wavelength, critically and stays approximately constant at 0.71. For smaller particle dimension, photons can travel longer path before scattering thus their path length distribution follows a heavy tailed distribution. At large carrier density, the fluctuation behavior deviates from usual power law and approaches towards Gaussian behavior. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/27771