The quality of optical components used in complex applications such as lasers, microscopes, and lithography systems, is critically influenced by surface morphology. The majority of these components lenses, mirrors, beamsplitters, polarizers, etc. are covered by thin film optical coatings. Hence, important properties of the optical elements such as optical scattering, are significantly affected by the surface microstructure of the thin film coating. With the ongoing trend of todays optical lithography towards shorter wavelengths (e.g. lithographic objective shifting from 248nm to 193nm), thin film research and industry are facing drastically increasing requirements for low-scatter optics in the UV, and deep UV, spectral region.