Characterization of inhomogeneous optical interference films using a complex parabolic profile model

The evaluation of the inhomogeneity of the complex refractive index n-ik throughout the thickness of a thin optical film is an important topic. In a previous work, regarding the n inhomogeneity, we found that the assumption of a model with a parabolic n profile throughout the film thickness allows us to characterize inhomogeneous films and to evaluate the n inhomogeneity even when the parabolic model is not realistic. Here the author completes the work by introducing a film model which also has a parabolic k profile and by describing a procedure for the unequivocal determination of the complex parabolic model parameters from normal incidence spectrophotometric measurements of T( lambda ), R( lambda ) and R'( lambda ).