Fabrication of a Random Laser by Embedding Copper Oxide Nanoparticles in Nonmetallic Host Media

In this work, a simple, low-cost method for fabricating random gain media from Rhodamine B dye solution containing highly-pure CuO nanoparticles in transparent resin hosts is proposed. The spectroscopic characteristics of the dye solution samples were investigated with varying dye concentrations, along with nanoparticles of different particle sizes and concentrations. The fabricated samples were excited using two laser sources (405 and 530 nm) to record the fluorescence spectra. Our findings indicate that nanoparticles ranging in size from 15 to 78 nm may not have a significant impact on the fluorescence intensity or the peak wavelength at which maximum fluorescence occurs. Additionally, the fluorescence peak width, centered around 595 nm showed minimal sensitivity to the variation in particle size. The optimal concentration of nanoparticles in the dye solution was determined based on the optimum values of scattering spectral width and anisotropy parameter. Subsequently, the gain coefficient was calculated and correlated with these two parameters. It was found that the samples with the highest fluorescence intensity can be achieved using dye dissolved in transparent resin at a molar concentration of 5 × 10⁻⁵ M, containing 0.03–0.04 mg of CuO nanoparticles with a particle size of 78 nm.