Light Scattering by a Dielectric Film with Periodically Varying Refractive Index Profile

Abstract

We study the scattering of light by a dielectric film with a periodic gradation of the refractive index along its thickness. The intensity of the scattered light is calculated in the scalar wave approximation, in which the periodicity of the refractive index contributes in two different ways namely (a) creating periodic fluctuations in the phase of the light beam thus creating a periodically corrugated wave front and (b) in creating changes in the amplitude of the light beam as it progresses across the thickness of the dielectric film. The scattered intensity is found by using the Fresnel formulae. It is seen that the scattered intensity follows a Raman Nath type expression, from which the optical parameters of the film can be determined.