介绍了一种基于中等口径光斑的新型激光预处理技术。采用基频最大输出10 J的Nd: YAG调Q激光器，获得了直径5 mm、能量密度满足预处理需求的中等口径光斑。较之于小光斑处理方案，采用中等光斑进行扫描，可以显著压缩大口径光学元件的预处理总耗时。为了验证效果，搭建了实验平台，在陪镀片上开展了光斑扫描与损伤阈值测量实验，设计了合理的中等光斑预处理流程，并对阈值提升效果进行了验证。在此基础上，开展了正式元件的预处理实验，采用大行程二维电动位移台，对430 mm×430 mm口径的金属铪蒸发工艺高反膜元件进行了夹持和扫描。实验结果表明，经处理后的高反薄膜元件初步达到了27 J/cm2的阈值水平，证明了该技术对薄膜抗损伤能力的提升效果。

A novel laser conditioning method based on mid-size laser spot is introduced. A Nd: YAG laser with 10 J max energy output at 1064 nm is adopted to form a 5 mm, fluence-qualified beam spot. Compared with the small-size spot type, this method has significant advantage in time saving. Experimental setup is built for verification. First, laser scanning and damage testing are carried out on small samples. The results demonstrate an obvious effect of laser conditioning, and the best flowchart for large-aperture optics is also verified. Furthermore, the conditioning experiment to large-aperture optics with reflective film prepared by hafnia evaporating is done. A 2D-motorized motion stage is applied for the handling and scanning of 430 mm×430 mm size optics. Experimental results indicate that a damage threshold of 27 J/cm2 can be achieved after the conditioning procedure. The effect of this technique is well demonstrated.