Dual-color plasmonic random lasers for speckle-free imaging.

A dual-color plasmonic random laser under single-excitation is achieved in an ultrathin membrane doped with binary quantum dots and gold nanorods. The gold nanorods tune the luminescence lifetime and emission efficiency of quantum dots. Under single excitation, low-threshold random lasing is observed. Green random lasing at 547 nm is 'turned on' and red random lasing at 630 nm is greatly enhanced by the transversal and longitudinal surface plasmon resonance of the gold nanorods, respectively. Speckle-free color imaging is achieved by using the proposed dual-color random laser source. These properties would facilitate the development of random lasers in fields of illumination and imaging.