The visible laser absorption property of chromium-doped polyvinyl alcohol films: synthesis, optical and dielectric properties

New films for visible laser filter were fabricated from poly(vinyl alcohol), PVA, and various levels of chrome(III) chloride, CrCl ₃ , by a known simple process named casting. The structure order degree, complex interaction, as well as optical filtering characteristic of the PVA + xCrCl ₃ (x = 0.037, 0.37, 3.7, 18.5 and 37 wt%) samples were investigated via the diffraction of the X-ray, Fourier transform infrared spectroscopy and UV/Vis/NIR spectrum, respectively, while the behavior of optical limiting was tested by set-up laser limiting measurement. The increment of Cr ³⁺ -doping level in the PVA gives some results as, (I) a marked increase in the degree of random structure of the samples, and (II) two clearly absorption peaks are seen around 428 nm and 608 nm with a progressive increase in the intensity and a slight shift to a higher wavelength. (III) Three distinguished energy gaps were clearly observed, as well as, (IV) the dielectric spectroscopy of the samples was decreased with increasing the Cr ³⁺ -doping, which contributes to the strong interaction among the mixtures. Furthermore, at concentrations above 0.37 wt% of Cr ³⁺ -doping, a notable decrease in the output detected laser power was observed.