Dual-band random laser based on positive replica of abalone shell

Random lasing from a polydimethylsiloxane substrate prepared from abalone shell by soft lithography was investigated. The substrate has better scattering efficiency than abalone shell and its groove structure can support both incoherent and coherent random lasing when covered with a layer of dye solution. When employing rhodamine 640 dye as gain medium, a dual-band random laser signal based on the mechanism of optical feedback intensity and mode competition can be observed, where the signals of the two bands are shown as incoherent and coherent random lasing regimes respectively. Speckle-free imaging is achieved by using incoherent and coherent random lasers as illumination sources and imaging effects are compared. This research shall promote the development of random lasers in the fields of illumination and imaging.