Experimental and theoretical investigation of statistical regimes in random laser emission

Abstract

We present a theoretical and experimental study aimed at characterizing statistical regimes in a random laser. Both the theoretical simulations and the experimental results show the possibility of three regions of fluctuations increasing the pumping energy. An initial Gaussian regime is followed by L\'evy statistics, and Gaussian statistics is recovered again for high pump pulse energy.These different statistical regimes are possible in a weakly diffusive active medium, while the region of L\'evy statistics disappears when the medium is strongly diffusive presenting always a Gaussian regime with smooth emission spectrum. Experiments and theory agree in identification of the key parameters determining the statistical regimes of the random laser.