Random Lasing Actions Induced by Silver Nanoprisms

Polymer films containing silver nanoprisms and laser dye have been fabricated as amplifying random media where silver nanoprisms and laser dye act as scatterers and optical gain medium, respectively. Above a certain pump threshold, the sample containing silver nanoprisms gives rise to very sharp lasing peaks with linewidth much less than 1.0 nm, while the sample without silver nanoprisms only shows amplified spontaneous emission even when pumped at high energy, implying the important role of silver nanoprisms in the occurrence of laser oscillation. The number of laser modes increases with pump energy. The effect of scatterer density on the laser threshold has been examined, revealing that the scatterer density has to be controlled to optimize laser performance. Given that there are few reports on metal nanoparticles-based random lasers up to now, it is expected that this work will lead to extensive research toward laser devices with low threshold and high emission intensity.