Polarized Reflection Spectrum of Thin Film on Metal Plate

The reflectance of radiation polarized parallel to the plane of incidence from a thin film on a metal plate was computed over the region of an absorption band in the infrared or in the visible. The rigorous equation of reflectance was used in the calculation and the change of sensitivity with the change in the incident angle, as well as the deformation of the band shape and the shift of the band peak, was observed in various cases. The optical constants n and k of the film were taken from experimental curves (visible) or generated using damped harmonic oscillator models (infrared). The incident angle of maximum sensitivity changes with the change of the optical constants of the film and that of metal relative to the medium, but, roughly speaking, the maximum sensitivity can be obtained using an incident angle of about 60～85°. The deformation of the band shape and the shift of the band peak are generally small. The reflection spectroscopy of polarized radiation, both in the infrared and in the visible, can be used as a very potential technique for studying the structure of a thin film on bulk metal in any non-absorbing medium and the interaction of the metal with adsorbed molecules on it