微结构高度是衍射光学元件的重要加工参数之一。基于双层衍射光学元件的带宽积分平均衍射效率和微结构高度的关系, 分析并给出了微结构高度的优化设计方法。在满足光学系统性能要求的情况下, 通过适当地降低带宽积分平均衍射效率来减小微结构的高度。分别针对可见光、长波红外、红外双波段三种波段工作的双层衍射光学元件进行仿真分析。分析结果显示, 工作在长波红外波段的双层衍射光学元件的带宽积分平均衍射效率减小1.9%, 微结构高度能降低55%以上。该结论对于双层衍射光学元件的加工及应用有重要的意义。

The microstructure height is one of the important parameters of Diffractive Optical Elements (DOEs). On the basis of the relationship of Polychromatic Integral Diffraction Efficiency (PIDE) with the microstructure heights of Double-layer Diffractive Optical Elements (DLDOEs), the optimal design method was analyzed and presented. Under the premise of satisfying the performance requirements of the optical system, the reduction of the microstructure height can be realized by reducing PIDE. The DLDOEs operating in the visible light band, long-wave infrared band and two infrared bands were simulated and analyzed respectively. The analytical results showed that the microstructure height of the DLDOE operating in the long-wave infrared band could be reduced by more than 55% when its 1.9% PIDE was sacrificed with this method. This conclusion was of great significance to the fabrication and application of DLDOEs.