Coherent-incoherent random lasing based on nano-rubbing induced cavities

In this letter we present the results of studies carried out on poly(n-vinylcarbazole) doped with the well-known DCM laser dye. We show that the simple incorporation of highly luminescent dye into a polymeric matrix can form an efficient solid state laser material. Naturally occurring inhomogeneities of a polymeric layer prepared by a drop casting process can scatter out light emitted in the process of photoluminescence in such a way that feedback is introduced to the system and coherent and incoherent random lasing can be observed. Moreover we show that after a nano-scale rubbing process the random lasing phenomenon occurs for a lower energy density of pumping light as compared to the virgin sample, and changes the light amplification nature from incoherent to coherent.