Tunable random lasing in Au@Fe3O4, Fe3O4@Au core shell nanoparticles under external magnetic field

Abstract

This work aims to control the random laser performance using magneto-plasmonic Fe3O4@Au and Au@Fe3O4 core shell nanoparticles as scatterer points in Rh6G dye. For this purpose, nanoparticles were produced via laser ablation in liquid method and mixed together in a dye medium. After characterizing samples through transmission electron microscopy and florescence spectra in the visible region, the samples were pumped via second harmonic generation of Nd: YAG laser and random lasing action were gathered by spectrometer. These measurements were performed with and without external magnetic field in four different magnetic field strengths of 1.08, 2.35, 17.7, and 20.7 mT. Our results revealed good full width at half maximum of laser efficiency in the samples exposed to the external magnetic field. In addition, using the external magnetic field, the samples with larger Fe3O4 core NPs and smaller shell thicknesses indicated a better ability to achieve a tunable random lasing under the external magnetic field.