IR Antireflection Coating

Broadband Antireflection Coating are designed and manufactured on Ge substrates in8-12um IR range and DLC coating. The Thin-film materials Ge、ZnS and YF3are produced by electron-beam deposition. A method of designing IR antireflection coating using the theory of inhomogeneous coating was presented. The film designed has been proves the result of optimization is perfect. The substrate is chosen in regard to its optical and mechanical properties.Ge ubstrates in8-12um IR range and DLC coating is very important of air windows.It is extensive application in spaceflight、weather、remote sensing.This research consists in designing and producing a8-12um antireflection coating for this lens. Although this spectral range is rather large, there is no great theoretical difficulty for the synthesis of such a coating since the substrate is of high refractive index. Major difficulties come from the choice of materials for the arrangement of manufacturing coating and DLC coating. It is more difficult to find a satisfactory low-index material since the choice is mainly limited to fluorides. These materials usually present a porous microstructure that induces poor durability, and water absorption during the period of deposition. Moreover, fluorides are not perfectly transparent to as great as12um. We choose yttrium fluoride for this research and coating is assistant of RFsource after study and analysis, and use computer-aided design, a method to correct the deviation between theory and experiment data when a Broad-band anti-reflective coating was manufactured with vacuum coating process. The method gets a good result.It is good result in PECVD machine of shen ke yi.