Black chromium coatings : experimental and calculated optical properties using inhomogeneous medium theories

Abstract

Bulk composition, surface and volume structures and optical characterization of selective black chromium coatings used for photothermal conversion of solar energy are presented. A model of the optical properties, taking into account all these parameters and using Maxwell Garnett and Effective Medium Theories for the determination of an effective dielectric constant for the inhomogeneous and rough media, is then developed. The influence of different roughness profiles is considered. The optical behaviour obtained with the different theories is examined and the limitations of these theories are discussed