Influence of fifth-order nonlinearities on the statistical fluctuations in emission intensities in a photonic open-cavity complex system

High-order nonlinear optical effects have become an important feature of photonic systems, both ordered and disordered. In this work, a very large and robust set of experimental data obtained from the emission spectra of a trivalent neodymium ion-based random laser, whose action mechanism relies upon gain and disorder, was characterized in detail. Using an effective model, it was possible to describe how the optical nonlinearities of the disordered gain medium affect the statistical behavior of the intensity fluctuations of the random laser for excitations close to and well above the laser threshold. A theoretical framework is presented and, in particular, in the regime well above threshold a nice fit to the experimental data is obtained with a distribution that incorporates nonlinearities up to fifth order, the Izrailev distribution.