Enhancement of Random Laser Properties on Solid Polymer Films by Increasing Scattering Effect

We study the properties of solid-based random lasers by observing spectral emission shape, emission intensity, emission line width, and lasing threshold. Random lasers based on solid polymer film are prepared by combining titania nanoparticles with rhodamine 640 in poly(vinyl alcohol) (PVA) water solution. We compare samples with and without scatterers. Adding nanoparticles to the samples narrows the emission spectrum, and the lasing threshold can be observed. The amount of titanium dioxide (TiO2) or titania nanoparticles is varied and affects the properties of random lasers. The spectral emission line width becomes narrower, and the lasing threshold decreases when the amount of titania increases. Results obtained show that the properties of solid-based random lasers can be improved by increasing scattering, which enhances the feedback mechanism. The enhanced properties of random lasers are very useful for creating a reliable optical device for future applications in medical and biosensing fields.