基于斜入射衍射光学元件的正常工作模式,建立了斜入射下入射角度和入射波长对双波段双层衍射光学元件衍射效率影响的数学模型,给出了对应双层衍射光学元件的优化设计方法。通过在入射角度范围内优化设计波长对,计算双层衍射光学元件微结构高度,确保了斜入射时双层衍射光学元件仍具有高衍射效率,弥补了双层衍射光学元件的缺陷。该方法能够指导双波段折衍混合成像系统的设计,也可以扩展至多波段多层衍射光学元件的设计中。依据该方法,设计了一套基于双层衍射光学元件的中/长波双波段折衍混合光学系统。结果表明,与常规设计相比,该方法的设计理论更加合理,设计结果更优。

Based on the normal working mode of a diffractive optical element (DOE) under oblique incidence, a mathematical model about the effects of incident angle and wavelength on the diffraction efficiency of a dual-band double-layer DOE under oblique incidence is established, and the optimal design of the double-layer DOE is presented. By optimizing the design wavelength pair within the incident angle range, the microstructure height of the double-layer DOE is calculated and the high diffraction efficiency of double-layer DOE under oblique incidence is realized, which makes up the defects in the double-layer DOE, guides the design of the dual-band hybrid imaging system, and can be extended to the design of a multi-band multi-layer DOE. Based on this method, a hybrid middle/long dual-band infrared optical system is designed. The results show that compared with the conventional method, it possesses a more reasonable design theory and a better design result.