Statistics of quality factors in three-dimensional disordered magneto-optical systems and its applications to random lasers

We have investigated the distribution of quality factors P(Q) of three-dimensional disordered systems composed of pointlike magneto-optical scatterers under the influence of an external magnetic field, both in the diffusive and localized regimes of light transport. P(Q) is shown to exhibit the same behavior of the distribution of delay times obtained in previous studies within different models to describe wave propagation in random media, such as the Anderson and the kicked rotator models. From the analysis of P(Q) we conclude that exponentially localized (and prelocalized) electromagnetic quasimodes depend on time-reversal symmetry. We suggest that this dependence could be explored in the development of a magneto-optical random laser, in which the threshold could be tuned by the application of a magnetic field. We also argue that such laser could be used to experimentally test if prelocalized modes are at the controversial origin of random lasing with coherent feedback in diffusive systems.