设计了应用于神光-Ⅲ装置的汤姆孙散射光收集系统。采用折反式双卡塞格林结构,实现了在有限口径内长距离的像传递,解决了紫外透射材料选择困难的问题。通过纠正镜的优化设计,使超长焦距透镜的加工、检测简化。通过选择适当的中间像面的放大倍率,降低了次反射镜的遮光比。通过在一次像面附近增设透射光学元件,实现了两组光学系统的有效耦合。在中间像面设置十字分划板方便了系统安装瞄准操作。系统总长5 m,最大元件口径190 mm,视场范围2 mm,放大倍率为1.5,物方F数为10,物方分辨率优于20μm。 The Thomson scattering light collection system was designed for SG-III device. The use of folding double Cassegrain green structure, to achieve a limited length of the aperture within the image transmission, to solve the problem of UV transmission material selection difficult. By correcting the optimal design of the mirror, the processing of the ultra-long focal length lens is simplified. By selecting the appropriate middle of the magnification of the image plane, reducing the secondary mirror shading ratio. By adding transmissive optical elements near the primary image plane, effective coupling of the two optical systems is achieved. Setting the cross reticle in the middle of the image facilitates the system installation aiming operation. The total length of the system is 5 m, the maximum component diameter is 190 mm, the field of view is  2 mm, the magnification is 1.5, the object-side F-number is 10, and the object resolution is better than 20 μm.