红外双层衍射光学元件衍射效率研究

摘要

红外衍射光学系统中衍射元件的设计波长直接影响光学系统的衍射效率.介绍了常见的三种红外材料,利用整个波段(3~14μm)衍射效率的平均值作为评价红外双波段衍射效率的因子,分别模拟了三种不同材料组合下,561种设计波长组合的平均衍射效率.结果得出:三种材料的不同组合,在与之相对应的设计波长下,其衍射效率平均值均可达到96%以上.设计了含有双层衍射元件的中远红外光学系统:入瞳直径EPD=33mm,视场2ω=9.2°,焦距f′=50mm,中波红外的传递函数(MTF)在40lp/mm所有视场达到0.6,长波红外在40lp/mm所有视场达到0.2.%In terms of the infrared optical system,its diffraction efficiency is directly affected by the design wavelength. This paper mainly simulated three combinations of common infrared materials in 561 combinations of design wave-lengths. During the simulation,the average diffraction efficiency in the wave band was regarded as the evaluation factor. It could be found that when the combination of different materials at the design wavelengths is used in the design of DOE, theoretically, all the diffraction efficiencies of the DOE are more than 96%. Based on the theory in the paper, the Mid-Wave and Long-Wave infrared diffractive optical systems were designed:EPD=33mm, FOV=9.2 degrees, Focal Length=50mm,the Modulation Transfer Function (MTF)in 40lp/mm in all fields more than 0.6,MTF in 40lp/mm in long-wave more than 0.3.