Optical Filters

Thin film filters are usually used as infrared filters because of their long transmission wavelength. The latter is a low-level, multistage series solid Fabry Perot interferometer by alternately forming metal dielectric metal films or all dielectric films with a certain thickness with high refractive index or low refractive index on a certain substrate by vacuum coating method. The choice of film material, thickness and series mode depends on the required central wavelength and transmission bandwidth λ determine.