结合谐衍射光学元件特殊的消热差以及对波面进行任意整形的特点, 针对现代最先进的像元尺寸为30 μm、 像元数320×240的红外双色探测器, 提出了一种轻小型双光谱超宽温度红外探测成像系统方案, 利用折射/谐衍射结构实现了超宽温范围内的被动式消热差红外成像探测, 仅用三片镜子的单结构就可实现系统在3.8～4.2和8.8～11.2 μm双光谱处在-120 ℃～200 ℃温度范围内同时探测。 系统仅使用锗和硒化锌两种材料, 引入了一个非球面和一个谐衍射面, 实现了消热差、 消色差和结构简单轻量化, 设计结果表明, 该系统在-120～200 ℃温度范围内, 3.8～4.2和8.8～11.2 μm光谱处的最大均方根半径值分别为19.07和17.75 μm, 小于红外探测器的像元尺寸30 μm, 在红外探测器两个像元内, 3.8～4.2和8.8～11.2 μm光谱处的能量集中度分别优于88.7%和82.4%, 成像质量良好, 方案工程实现性好, 设计方法和设计结果合理可行。

Because harmonic diffractive optics elements has special achromatism, athermalization and arbitrary phase modulation characteristics, an infrared detection system method with dual spectrum and wide temperature range was presented based on the most advanced infrared dual color detector which had a format of 320×240 and the pixel pitch of 30 μm. A hybrid refractive/harmonic diffractive infrared detection system with dual spectrum and wide temperature range was designed. The working wavelength range was 3.8～4.2 and 8.8～11.2 μm. The system was only consisted of three lenses, including one aspheric surfaces and a harmonic diffraction surface, which made the system have compact structure and light weight. In the temperature range -120～200 ℃, the RMS radius of spot diagram in 3.8～4.2 and 8.8～11.2 μm was 19.07 and 17.75 μm respectively, which is less than the pixel size of infrared detector with 30 m, the enclosed energy in 30 μm, the enclosed energy in 3.8～4.2 and 8.8～11.2 μm is 88.7% and 82.4% in two pixel size. The method and structure was convenient and predominant. It was proved that the design was feasible.