Spin Glass Behavior of Random Lasers: Experiments

In this chapter, the authors summarize the findings after a brief and simple description of Replica Symmetry Breaking (RSB) and spin glass theory, aimed toward experimentalists and researchers not specialized in statistical mechanics theory. In window glass or any amorphous solid, the atomic bond structure is highly irregular; in contrast, a crystal has a periodic pattern of atomic bonds. Similarly, in a ferromagnetic solid magnetic spins are all aligned. Transition from paramagnetic to glassy states in random lasers has been also compared to the transition from diffusive to super diffusive. Very recently, RSB theory has been applied to obtain the real time maps of the laser activity in a heterogeneous random laser (RL). The RLs are made of polymeric ribbon-like and highly porous fibers with evident RL action from separated micrometric domains that alternatively switch on and off by tuning the pumping light intensity.