Low-level scattering and localized defects

We investigate the origin of low-level scattering from high-quality coatings produced by ion-assisted deposition and ion plating. For this purpose we use the polarization ratio of light scattering to separate surface and bulk effects that characterize the intrinsic action of the thin-film materials. In the first step the method is tested and validated at scattering levels greater than 10(-5). In the second step it is applied at low levels, and the results reveal some anomalies. To conclude, we perform a detailed analysis of scattering resulting from the presence of a few localized defects in the coatings.