为了明确近红外成像光学系统对杂散光的抑制能力,设计了一个光谱为0.75 μm ~1 μm,焦距12.002 mm,F/1.8,视场15°×15°的光学系统,其结构为改进型的双高斯结构.实验结果表明:设计的光学系统的各视场光斑在艾瑞斑内,焦移量最大为4.9 μm,球差约为1 μm,垂轴像差最大为3 μm,MTF接近衍射极限.对设计的光学系统进行了杂散光评估和杂散光抑制,得到了杂散光抑制前后的点源透射比.分析结果表明:与未加遮光罩相比,加入遮光罩的光学系统PST值下降了76.6%~87.5%.

In order to clear the suppression ability of optical system to stray light,we designed the optical system with a improved double gauss structure,whose spectrum was 0.75 μm ~1 μm,focal length was 12.002 mm,F was 1.8,field of view(FOV)was 15°×15°.We obtained a optical system whose spot of every FOV was in the airy,max shift was 4.9μm,spherical aberration was about 1 μm,max transverse aberration was 3 μm,modulation transfer function(MTF)was closed to the diffraction limity.Furthermore ,we carried on the evaluation and suppression of stray light,got the point source transmittance(PST)of stray light.Compared with the optical system without lens hood,the value of PST decreases by 76.6%~87.5% after adding the lens hood.