Random lasing from dyed polystyrene spheres in disordered environments

Advance designs of random lasers toward the development of miniature laser systems are in demand. Random lasing from Rhodamine-B dye doped polystyrene microparticles was demonstrated. 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 solution and in photonic glass. Incoherent feedback occurred in both the cases, and laser emission was obtained with a spectral line width of ∼10 nm. Optimized number densities of bare and dye doped polystyrene microparticles required for random lasing action in such systems were evaluated. Although both disordered media showed random lasing with similar number densities of the microparticles, the lasing threshold in the case of photonic glass was lower in comparison to binary colloidal solution. This was because of higher index contrast and larger filling fraction of microparticles in the case of photonic glass. Lasing results obtained for photonic glass were compared with their previous results of Bloch lasing in photonic crystal synthesized using similar dye doped polystyrene microparticles.