Optical constants of gamma-irradiated silver-doped PVA in the near-infrared range

Abstract

Pure and gamma-irradiated silver-doped polyvinyl alcohol 'PVA' samples are fabricated, and their optical constants are experimentally determined through the measurement of the reflectance and the transmittance. Using the thin-film model, an iterative method is used to solve for the real and imaginary parts of the refractive index, in the near-infrared (NIR) region. The retrieved refractive index values are verified through a comparison between the theoretical calculations and the practical measurements of the transmittance. The refractive index shows a big increase in the absorption loss of the polymer, when compared to pure PVA. This qualifies the fabricated films for new applications such as optical plasmonic circuits, optical absorbers, solar energy harvesting and sensors in the NIR region. More insight on the functional groups that exist in the fabricated specimens is given by Fourier transform spectroscopy in the mid-infrared range from 400 to 4000 cm-1.