In high power laser facility for inertial confinement fusion research, final optics assembly (FOA) plays a critical role in the frequency conversion, beam focusing, color separation, beam sampling and debris shielding. The design and performance of FOA in SG-II Upgrade laser facility are mainly introduced here. Due to the limited space and short focal length, a coaxial aspheric wedged focus lens is designed and applied in the FOA configuration. Then the ghost image analysis, the focus characteristic analysis, the B integral control design and the optomechanical design are carried out in the FOA design phase. In order to ensure the FOA performance, two key technologies are developed including measurement and adjustment technique of the wedged focus lens and the stray light management technique based on ground glass. Experimental results show that the design specifications including laser fluence, frequency conversion efficiency and perforation efficiency of the focus spot have been achieved, which meet the requirements of physical experiments well.

中文翻译：

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SG-II 升级激光设备中最终光学组件的设计和性能

在用于惯性约束聚变研究的高功率激光设备中，最终光学组件 (FOA) 在频率转换、光束聚焦、颜色分离、光束采样和碎片屏蔽中起着至关重要的作用。这里主要介绍SG-II升级激光设备中FOA的设计和性能。由于空间有限，焦距短，设计了同轴非球面楔形聚焦透镜并将其应用于FOA配置中。然后在FOA设计阶段进行鬼像分析、聚焦特性分析、B积分控制设计和光机设计。为了保证FOA的性能，开发了楔形聚焦透镜的测量和调整技术和基于毛玻璃的杂散光管理技术两项关键技术。