基于组合Fabry-Perot 膜系的中波红外双色滤光片设计

There are several methods to design dual-band-pass optical filters, such as automatic optimization, design using buffer and combinatorial layers, F-P filter with thick spacer layers; repeating blocks of F-P filter with double peaks and F-P filter with a fractal structure, etc. But they have certain limitations either in design that has specific requirements on band-width and distance between two channels, or in the technique implementation of the film stack. Using the method of combining two F-P filters with a transmission band, which is obtained from optimization of target fitting, the problem of designing a wide band-width and large channel span dual-band-pass filter is effectively solved. Using the materials of Germanium and Silicon monoxide, a good spectrum performance dual-band-pass optical filter is designed with a layer number of 38. The relative band-width of both path-bands are 9%, the ratio between two channels'wavelength position can be adjusted from 1.4 to 5.0, the steepness of all the band edges are no more than 2.0%. This kind of coatings structure has strong technological practicability as well as good adjustability of both pass-band-width and channel position. © 2016, Chinese Laser Press. All right reserved.