DIFFUSE-REFLECTANCE AND TRANSMITTANCE SPECTRA OF AN INTERFERENCE LAYER .1. MODEL FORMULATION AND PROPERTIES

A model for the calculation of the diffuse reflectance and transmittan ce of a single interference layer with rough interfaces on a transpare nt substrate is presented. The model is based on electric field calcul ations and scalar scattering theory, and it assumes that the interface s of the layer are totally uncorrelated. Examples are given of calcula ted spectra in which the parameters of the model are varied systematic ally to show the influence from different interface roughness and refr active index combinations as well as absorption in the film. A wavelen gth-dependent effective root-mean-square roughness is introduced. This depends on the nature of the roughness, and the bandwidth limits are given by the experimental conditions. Finally, total integrated scatte ring spectra are calculated and the importance of taking multiple refl ections in the substrate into account is shown.