针对可见光与红外大口径薄膜衍射光学系统在空间上应用的可行性问题,提出基于二维时域有限差分法的大口径衍射光学成像特性的仿真模型与快速分析的计算方法。首先充分考虑大口径衍射光学元件的亚波长微结构尺寸的电磁场调制特性,建立亚波长结构尺寸的衍射光学系统成像特性分析模型;然后通过矢量化编程和GPU加速运算提出快速求解方法,有效解决由矢量计算所致计算量庞大的问题;最后利用建立的成像特性分析方法对大口径衍射光学系统进行成像特性分析实验。实验结果表明:该方法可在有效表征亚波长微结构衍射光学系统成像特性的基础上,实现衍射光学元件成像特性的快速分析。

In this paper, aiming at the feasibility of the visible and infrared large-aperture membrane diffractive optical systems in space application, we present a simulation model and fast analysis and calculation method of large-aperture diffraction optical imaging characteristics based on the two-dimensional finite difference time domain. First, we fully consider the electromagnetic field modulation characteristics of the subwavelength microstructure size of the large-aperture diffractive optical element, and establish the imaging characteristics analysis model of the sub-wavelength structure size diffractive optical system. Then, through vectorization programming and GPU acceleration calculation, we propose a fast simulation calculation method to solve the problem caused by vector calculation. Finally, we take a large-aperture diffractive optical system as an example and verified the imaging characteristics using the established imaging characteristics analysis method. Experimental results reveal that the proposed method can effectively characterize the imaging characteristics of the subwavelength microstructure diffractive optical system, and realize a rapid analysis of the imaging performance of diffractive optical elements.