Deviations from light scattering envelopes of simple vectorial theories

Publisher Website
Google Scholar
Abstract
First order simple theories are often satisfactorily applied to interpret light scattering by surfaces commonly used in optics, when they are either well enough polished surfaces, or inversely, ground surfaces exhibiting facets large compared to the wavelength. In intermediate cases discrepancies related to polarisation phenomena do occur. They are interpreted by effects of discrete defects producing micro-reflections which are not taken into account by the theory usually applied to polished surfaces. A measure of the deviations allows in some cases to retrieve the roughness power spectrum of the already polished areas during the working out process. Besides, an attempt is made to explain the origin of the depolarized light not predicted by first order theories. An experimental investigation carried out on samples with various roughness heights supports the computed values and suggests the use of a depolarisation ratio to characterize ground or partially polished surfaces.