Ellipsometry of light scattering from multilayer coatings

Abstract

A scatterometer is extended and allows us to perform ellipsometric measurements on scattered light in each direction of space. Experimental data are given for single thin-film layers and optical coatings and reveal unexpected results. The phenomena are investigated by means of the electromagnetic theories of surface and bulk scattering that emphasize the role of partial correlation and localized defects.

Ellipsometry of speckle patterns for the analysis of optical inhomogeneities (surfaces and bulks)

“…Scattering data have then been extended to angular phase measurements thanks to interferences between the two polarizations. That is the Ellipsometry of AngleResolved Scattering (EARS) [8,9]. In a recent work limited to slightly inhomogeneous samples, we demonstrated the validity of the E.A.R.S.…”

Angular scattering and ellipsometry of the scattered field: multiscale roughness and contamination of surfaces

“…Angle resolved ellipsometry of the scattered field has been presented as an original technique developed at Institute Fresnel to complete light scattering intensity measurements [4]. The experimental results can be investigated via electromagnetic theories of surface and bulk scattering.…”

“…In the case of a bare substrate, we can show [4,5] that the variations of the polarimetric phase do not depend on the surface profile or bulk inhomogeneity, but on the origin of scattering. Figure 4 shows these results of calculations and measurements in the case of bulk or surface scattering substrates.…”

“…This phenomenon can be measured but is not predicted with first order theory in the incidence plane. A phenomenological approach has been performed and presented in a previous paper [4]. It was shown that a depolarization of 10 -4 causes the phase term to vary from 0° to 25°.…”

“…In a first part, we will show how angular scattering measurements at wavelengths varying from the UV to the IR and the development of electromagnetic theories at Institut Fresnel Marseilles permit to quantify the multiscale roughness of components. In a second step, we show how the scatterometer has been extended to allow ellipsometric measurements of the scattered light in each direction of space [4]. Results can be investigated by electromagnetic theories and permit to directly separate bulk and surface effects in the case of bare substrates and to reveal the high sensitivity of the polarimetric phase difference to the presence of contaminants on surfaces, even in the case of first order contaminants, that is to say whose size is in the same order as the substrate roughness.…”