为了优化对大口径激光探测组件灵敏度、角度参数等特性的测量能力, 减小因高斯光束光强分布中间强、边缘弱的特点造成的测量值差异, 基于小口径非球面镜组光束整形及高倍率扩束技术, 设计了大口径均匀激光光束产生装置,提出了基于光强分布、非球面镜非球面度、光线光程差的综合优化整形方法。 结果表明, 设计的开普勒型非球面整形镜组非球面度小于20 μm, 工作束宽5 mm, 输出平顶光束均匀性为92.8%; 设计的40×高质量扩束系统, 与非球面镜组相匹配可实现2 m距离内150 mm口径均匀光束, 可获得优于94.2%的150 mm大口径均匀光束输出。该研究对激光测量与标定系统的工程化设计是有帮助的。

Laser beam alignment is very important for high-power laser facility. Long laser path and large-aperture lens for alignment are generally used, while the proposed alignment system with a wedge by far-field sampling technique reduces both space and cost requirements. General alignment system for large-aperture laser beam is long in distance and large in volum because of taking near-field sampling technique. With the development of laser fusion facilities, the space for alignment system is limited. A new alignment system for large-aperture laser beam is designed to save space and reduce operating costs. The new alignment for large-aperture laser beam with a wedge is based on far-field sampling technique. The wedge is placed behind the spatial filter to reflect some laser beam as signal light for alignment. Therefore, laser beam diameter in alignment system is small, which can save space for the laser facility. Comparing to general alignment system for large-aperture laser beam, large-aperture lenses for near-field and far-field sampling, long distance laser path are unnecessary for proposed alignment system, which saves cost and space greatly. This alignment system for large-aperture laser beam has been demonstrated well on the Muliti-PW Facility which uses the 7th beam of the SG-Ⅱ Facility as pump source. The experimental results indicate that the average near-field alignment error is less than 1% of reference, and the average far-filed alignment error is less than 5% of spatial filter pinhole diameter, which meet the alignment system requirements for laser beam of Multi-PW Facility.