  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.
