Rugate optical filter systems

摘要

A method for fabricating graded refractive index (rugate, optical filters as well as complex rugate filters having prespecified refractive index verses thickness profiles is disclosed. A plurality of at least two different compatable thin film deposition source components of different refractive index, which are stoichiometrically combinable in variable proportion, such as silicon nitride and silicon oxide, or zinc sulfide and zinc selenide, are used to form a thin film material with a refractive index which varies as a function of the proportions of the components. Each source component is separately laser flash evaporated and codeposited on a substrate to form a coating while monitoring the physical and optical thicknesses of the coating, to allow adjustment of the respective laser flash evaporation rates of the source components.