设计了一种基于谐衍射的红外双波段共口径消热差光学系统。此光学系统的工作波段为 3～5 .m及 8～12 .m，焦距为 45 mm，F/#为 2，双色探测器为 320×256、30 .m制冷型探测器。谐衍射光学元件改进了衍射光学元件在宽波段上的大色散问题，解决了衍射光学元件在宽波段上的色散严重和衍射效率低下的问题。该光学系统采用谐衍射光学元件消宽波段色差和宽温度范围热差，使中波红外和长波红外在不同衍射级衍射实现谐振共焦成像，使用较少光学元件，校正了双波段红外光学系统的像差和热差。基于谐衍射的红外双波段共口径消热差光学系统在改善像质、减小体积重量、宽波段消热差等方面表现出传统光学系统不可比拟的优势。随着双波段探测器和谐衍射透镜研发制造技术的进一步发展，双波段光学系统必将在目标跟踪、识别、精确打击等**系统中得到广泛应用。

We proposed an infrared dual-band common aperture optical system, without thermalization, based on harmonic diffraction in this study. The optical system has two working bands of 3-5 .m and 8-12 .m, a focal length of 45 mm, a value of F/# of 2, and a resolution ratio of the frigorific double-color detector of 320×256 with a 30 .m pixel size. The harmonic diffractive optical element improves the large dispersion problem of the diffractive optical element over a wide wavelength band and solves the severe dispersion problem of the diffractive optical element over a wide wavelength band and low diffraction efficiency. The optical system uses harmonic diffractive optical elements to widen the chromatic aberration of the band and temperature range, so that the mid and long-wave infrared diffracted at different diffraction orders, to achieve resonant confocal imaging, and the dual-band infrared optical system are corrected using fewer optical components. This optical system also reflects the incomparable advantages of traditional optical systems with respect to improving image quality, reducing volumetric weight, and wide-band a thermalization. With the further investigation of the research and development (R&D) and manufacturing technology of dual-band detector harmonic diffractive lenses, this dual-band optical system could be widely used in military systems such as target tracking, identification, and precision strikes.