Random Laser and Replica Symmetry Breaking in SiO2-Rhodamine 6G xerogel powder

Random laser (RL) based on Rhodamine 6G (Rh6G) doped silica xerogel, fabricated by a conventional sol-gel (SG) synthesis, was observed around 590 nm, in a large band typical from dye RLs. Different from other previous works, where the xerogel is just impregnated or infiltrated with a dye solution, here the Rh6G was added during the SG synthesis. The obtained material was grinded using a mortar and a pestle, and the resulting powder was carefully packed in a sample holder and pumped at 532 nm using a 6 ns pulsed laser. We used spectral and images measurements to perform statistical analysis and describe experimentally the Parisi replica breaking symmetry (RSB) phenomenon in a complex system. These results show that RSB obtained from image is a promising method for RL characterization. Indeed, by calculating the RSB maps, we demonstrate that the RL emission is not a homogenous process, depending on the scattering and gain properties of different regions.