Optical Properties of Surface Films. II

Publisher Website
Google Scholar
Abstract
Measurements of ellipticity of light reflected from a film‐coated metal surface have been made for films varying in thickness from 25 to 40,000A. It was found that the approximate formulas of Drude which express as a function of the film thickness the ratio and phase difference of the components vibrating in the plane of incidence and perpendicular to it are valid for thin films. The general formula of Drude expressing the phase shift as a function of the film thickness represents with a fair approximation the experimental results obtained with metallic slides coated with films of Ba stearate whose thickness is up to the order of the wave‐length of light. Thus, for the first time, Drude's theoretical formulation has been verified experimentally. For films whose thickness is many times the wave‐length of the light used, there is a progressive divergence from Drude's general formula, the cause of which can possibly be due to the birefringence of the films which has been neglected in this work.