实现复消色差的超常温混合红外光学系统

讨论了利用二元光学元件实现红外光学系统消热差的原理和方法，分析了二元光学元件的色散特性及其在校正二级光谱中的优越性，给出了实现复消色差和超常温消热差的混合红外光学系统设计实例.该系统焦距100mm，相对孔径1/2，视场角6°，工作波段8—11μm；采用了两种最常用的硅和锗材料，共三片，结构简单.在-80—200℃的超宽温度范围内，成像质量稳定并达到衍射极限，约在系统0.7孔径处轴向像差曲线基本相交于一点，实现了系统的复消色差. 关键词： 红外光学系统设计 消热差 复消色差 折射/衍射混合光学系统

Design of a hybrid infrared apochromatic optical system beyond normal temperature

The principle and design method of employing diffractive optical element to athermalize an infrared optical system are discussed. An analysis is made on the diffractive optical elements dispersion characteristics and its superiority in correcting the second spectrum. A hybrid infrared optical system，as a practical application example，which has realized apochromatism and works beyond normal temperature, is presented. The parameters of the system are as follows: the focal length is 100mm，relative aperture is 1/2，field of view is 6°，and the working waveband is 8—11μm. In the system，only two materials，namely silicon and germanium, are used. The image quality of the system achieves the diffractive limit within the temperature range of -80—200℃. At about 0.7 aperture，three longitudinal aberration curves of the system intersect at one point，and the apochromatism of the optical system is achieved.