Random lasers with coherent feedback from highly transparent polymer films embedded with silver nanoparticles

We report on observations of random lasers with coherent feedback in highly transparent polymer films embedded with silver nanoparticles. The hybrid materials were fabricated via in situ synthesis method, through which silver nanoparticles were precipitated by thermal treatment. Sharp peaks with linewidth ∼0.5nm were observed to emerge on the broad emission background when the pump energy reached a threshold, together with unidirectional laser irradiation. Random lasers with coherent feedback induced by silver nanoparticles have been rarely reported, hence, we expect that this work will add an aspect to random lasers by using metal nanostructures to obtain coherent feedback.