Optical properties of polyamide films modified by implantation of cobalt ions

Abstract

Reflection and transmission spectra in the range 200–1100 nm of thin (40 μm) polyamide films implanted with Co+ ions of energy 40 keV at ion-current density 4 μA/cm^2 in the dose range 2.5•10^16–1.5•10^17 cm^–2 are measured. The implantation leads to a significant (up to 80%) decrease of transmission through the implanted films and an increase of reflection from both the implanted and nonimplanted sides because of carbonization of the surface layer and formation of cobalt inclusions in it. Transmission of light incident on the implanted and nonimplanted sides was simulated and the dose dependence of the effective refractive index of the modified layer was determined in the framework of two- and three-layer models including one or two modified layers and the undamaged part of the film. The effective refractive index in the studied dose range was within 1.3–2.1.