Tunable low power piezo-plasmonic random laser under external voltage

Abstract

This study was aimed to introduce a new kind of low power and tunable random lasers based on piezo-plasmonic core/shell nanoparticles (NPs) consisting of lead zirconate titanate and gold, mixed by different concentrations of Rhodamine B (RhB) dye. To get the random lasing, the sample was exposed to pulsed laser at the presence and in the absence of an external voltage. We got a gradual increase in the thermo-plasmonic properties by increasing the applied voltage on core/shell NPs, which depended on the boundary conditions between the shell and the core samples. By external voltage, the emission intensity was enhanced by decreasing the threshold lasing due to an increase in scattering, which more easily made a close loop path in the gain medium. Our results showed some spikes with the same pump energy in emission spectrum which confirmed the coherence random lasing. This phenomenon could be observed in PZT@Au NPs and it could not be observed in Au@PZT NPs in low and high concentrations. Furthermore, in lower pump energy, we observed low peak intensity in the emission spectrum and it increased as the pump energy overrode the lasing threshold. The emission spectrum became narrow with a sharp increase in the emission intensity, which we could reach a rapid decrease in the full width at half maximum (FWHM) of the emission intensity above the threshold. These results showed the possibility of using these new kinds of materials for low threshold and controllable random lasing.