Enhanced-performance and wavelength-tunable magnetically controlled random lasing based on magnetic-plasmonic nanoparticles.

High-performance and wavelength-tunable random lasing has a wide application prospect. We developed an enhanced-performance and wavelength-tunable magnetically controlled random lasing system based on R6G solution doped with FeO/Au nanoparticles (NPs), in which FeO/Au NPs could exhibit both magnetic and plasmonic characteristics. Compared to the FeO NPs, FeO/Au NPs could more effectively lower the random lasing threshold, which was 37.6% of that of the net gain medium. This is because the FeO/Au NPs exhibit the plasmonic effect and larger scattering cross section than the FeO NPs. In addition, the distribution of the FeO/Au NPs in the R6G solution could be effectively regulated by an external magnetic field; thus the random lasing emission modes could be tuned in real-time, and a switch between the random lasing and amplified spontaneous emission can be achieved by removing or applying the external magnetic field. This work provides a simple method to enhance the lasing properties and tune the emission wavelength simultaneously.