Calculation of electric field and absorption distributions in thin film structures

It will be shown how, by s straightforward extension of the usual matrix formalism for the calculation of transmittance and reflectance of thin film optical structures, the internal electric field distribution can be calculated. Consideration of the energy flux then allows one to calculate the distribution of absorption in the structure. The effects of absorption are included without approximation so that there is no restriction on the nature of the substrate or of any of the thin film media. Absorbing dielectrics, semiconductors or metal layers are allowed. Examples will be given of the application of the theory to antireflection coatings, high reflectance mirrors and interference filters.