Study of the absorption and emission spectra of polymeric films colored with laser organic dyes

This study focuses on the absorption and emission (fluorescence) spectra of two organic dyes, Rhodamine and Fluorescein. The dyes are prepared as liquid samples dissolved in a polyvinyl alcohol (PVA) polymer solution at different concentrations (0.01, 0.02, 0.03, and 0.04 mM). Solid samples in the form of PVA polymer films doped with Rhodamine and Fluorescein are also prepared using the casting method, in which the dyes are directly mixed with the polymer solution at different concentrations (0.01, 0.02, 0.03, and 0.04 mM), while maintaining a constant film thickness of 120 μm.The absorbance values of all prepared samples are measured using a UV–Vis spectrophotometer. The results indicate that increasing dye concentration affects the linear optical properties of the prepared samples, resulting in increased absorbance and decreased transmittance, consistent with the Beer–Lambert law. Increasing the dye concentration also results in higher calculated linear optical coefficients, including the linear refractive index and linear absorption coefficient, for all samples.Fluorescence spectra are measured using a fluorescence spectrometer, and the fluorescence lifetime and quantum efficiency are calculated to evaluate the emission properties of the studied dyes. The results indicate that the Rhodamine- and Fluorescein-doped PVA films possess promising optical properties, demonstrating their potential for advanced photonic and laser applications.