Multilayer protective coatings for IR optical windows

By using GexC1-x, BP and -Si as high index material and DLC as low index material, GexC1-x/DLC, BP/DLC and -Si/DLC multilayer protective coatings were designed and coated on long wave band IR windows such as ZnS, GaAs and Ge. Optical performance, micro-hardness and resistance to marine environment of these coatings were studied through experiments. Based on the characteristics of IR window and protective coating material, the results of experiments were discussed. The results show that GexC1-x/DLC multilayer coatings have best optical transmittance and BP/DLC multilayer coatings is best to resist marine environment.