ABSTRACT
A hybrid antireflective coating combining homogeneous layers and linear gradient refractive index layers has been deposited using different techniques. The samples were analyzed optically based on spectrophotometric and spectroscopic ellipsometry measurements under different angles of incidence in order to precisely characterize the coatings. The Lorentz-Lorenz model has been used to calculate the refractive index of material mixtures in gradient and constant index layers of the coating. The obtained refractive index profiles have been compared with the targeted ones to detect errors in processes of deposition.
ABSTRACT
Methods for the manufacture of rugate filters by the ion-beam-sputtering process are presented. The first approach gives an example of a digitized version of a continuous-layer notch filter. This method allows the comparison of the basic theory of interference coatings containing thin layers with practical results. For the other methods, a movable zone target is employed to fabricate graded and gradual rugate filters. The examples demonstrate the potential of broadband optical monitoring in conjunction with the ion-beam-sputtering process. First-characterization results indicate that these types of filter may exhibit higher laser-induced damage-threshold values than those of classical filters.
