基于多层衍射光学元件的位相延迟表达式, 提出了单点金刚石车削影响下的多层衍射光学元件衍射效率和带宽积分平均衍射效率的数学模型, 并给出了相应的分析表达式.以基底材料分别是硒化锌和硫化锌构成的多层衍射光学元件在近红外波段(1.4~2.5 m)的应用为例进行分析.结果表明表面粗糙度会导致多层衍射光学元件衍射效率和带宽积分平均衍射效率的明显降低, 从而降低了混合成像光学系统的成像质量.因此, 单点金刚石车削衍射元件时, 要根据使用需求制定合理的表面粗糙度加工误差.

Based on the expression of phase delay of the multi-layer diffractive optical elements, the mathematical model of diffraction efficiency and polychromatic integral diffraction efficiency under the influence of single-point diamond turning is proposed, and the analytical expressions are correspondingly provided. The application of the multi-layer diffractive optical elements whose substrates are composed of ZnSe and ZnS for each layer is simulated and analyzed in near-infrared waveband (1.4~2.5 m). The results show that the surface roughness error leads to a decrease in the diffraction efficiency and the polychromatic integral diffraction efficiency of the multilayer diffractive optical elements, making the imaging quality of the hybrid imaging optical system decreased. Therefore, when the single-point diamond turning is used to cut optical elements, the result is instructive to draw out justified limit surface roughness error according to usage requirements.