EXPERIMENTAL STUDIES OF INHOMOGENEOUS COATINGS FOR OPTICAL APPLICATIONS

A novel codeposition process has been developed for the fabrication of inhomogeneous optical coatings. These single-layer coatings exhibit composition and refractive index that vary continuously with thickness. Two types of inhomogeneous optical filters for antireflection and narrow band rejection applications, respectively, were experimentally fabricated using different vacuum deposition processes. The antireflection coating, composed of ZrO2 and MgF2, was prepared by electron beam coevaporation. The narrow band rejection filter, made up of SiO2 and TiO2, was codeposited by ion assisted, dual ion beam sputtering technique. The physical, chemical, and microstructural characteristics, as well as optical and environmental properties of these filters were evaluated.