Random lasers with coherent feedback have been obtained in highly transparent polymer films embedded with silver (Ag) nanoparticles. The hybrid materials were fabricated via in situ synthesis, through which Ag nanoparticles were precipitated by heat treatment. Sharp peaks with linewidth of similar to 0.3 nm emerge on a broad emission background when the pump energy reaches a threshold. Random lasers with coherent feedback induced by Ag nanoparticles have been little reported, and hence, we believe that this work brings about an important aspect to random lasers.
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Schematic of excitation-detection for random lasing (left) and emission spectra recorded over pump energies (E-p) of 0.43, 2.29, and 1.60 mu J (right). (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim