Real-time spectroscopy of solid-state random lasers

Abstract

Random lasers are the simplest sources of stimulated emission without a cavity, with the feedback provided by disorder-induced scattering in a gain medium. Since the first experimental observation of a lasing-like emission in a dye solution with scatterers took place, the incorporation of dye molecules into a solid host has attracted much interest in the development of new random lasers. Random laser action is demonstrated in two kinds of powder samples containing rhodamine 6G (Rh6G) doped SiO2nanoparticles which are either directly dispersed within pure silica particles or embedded in a silica gel matrix which is subsequently ground. Both organic-inorganic hybrid materials present different laser thresholds and emission features which are systematically studied and compared. The dependence of the emission kinetics, emission spectrum, random laser threshold and slope efficiency on the dye doped nanoparticles concentration is investigated in both cases. The laser-like emission dynamics can be accurately described by a light diffusive propagation model. The device behavior is close to a conventional ultrafast Q-switched laser, which is an interesting fact aimed to further applications. © 2011 Springer Science+Business Media B.V.