Random Lasing from Dyed Polystyrene Spheres in Disordered Environment

Advance designs of random lasers towards development of miniature laser systems are in demand. We demonstrated random lasing from Rhodamine-B dye attached to polystyrene micro-spheres. Bare polystyrene spheres were used as scatterers and these provided optical feedback to the gain. Random lasing was successfully demonstrated in two different disordered environments, in binary colloidal mixture solution and in photonic glass. Incoherent feedback occurred in both the cases and single wavelength lasing were obtained. The lasing threshold in case of photonic glass was lower in comparison to binary colloidal mixture solution. This was because of higher index contrast and larger filling fraction of micro-particles in case of photonic glass. Longer fluorescence lifetime of embedded dye was observed in photonic glass environment in comparison to ethanolic solution of the Rhodamine-B dye. Lasing results obtained for photonic glass were compared with our previous results of Bloch lasing in photonic crystal synthesized using similar dye doped polystyrene micro-spheres.