In situ and ex situ spectrophotometric characterization of single- and multilayer-coatings I: Basics

Optical spectrophotometry provides a powerful tool for the characterization of modern coatings, no matter whether they are manufactured for optical or non-optical applications. Spectrophotometry of coatings gives primary access to optical constants and their dispersion as well as to the film thickness. In a second step, the application of sophisticated KramersâKronig-consistent dispersion models gives further access to related quantities, including density, porosity, but also charge carrier density, crystalline structure, band structure and possible impurities of the coating. We will present and discuss the state of the art in spectrophotometry of single and multilayer coatings, including their in situ as well as ex situ versions. In situ spectrophotometry allows re-engineering as well as monitoring the deposition process of a growing coating, resulting in excellent specification adherence particularly in the field of optical coatings.