为实现石英玻璃表面凹槽的飞秒激光精密减薄加工，采用线扫描-面减薄的工艺手段，研究脉冲能量对烧蚀线槽形貌的影响，并以此为基础开展不同烧蚀线重叠率δ 的单层凹槽减薄实验，通过激光共聚焦显微镜对凹槽的槽深、侧壁角和底面粗糙度等形貌特征进行观测和分析。研究表明，当40%≤ δ ≤80%时，随着δ 的增大，凹槽深度增大、侧壁角减小；当δ =40%时，凹槽的槽深、槽宽、侧壁角分别为14.56 μm、261.8 μm 和59.1°。凹槽底面粗糙度Ra和Rz 随δ 的增大而减小，当δ 为80%时分别达到最小值0.19 μm 和1.23 μm；平行于扫描速度方向的轮廓算数平均偏差Ra′和微观不平度十点高度Rz′随δ 的增大呈现先减小后增大的趋势，当δ 为80%时，Ra′≈Ra、Rz′≈Rz；轮廓三维均方根偏差Sq随δ 的增大逐渐减小，最小值为0.16 μm。

In order to realize the precisely thinning of flute on the surface of quartz by femtosecond laser, the line-surface ablation process means are taken to study the effects of the pulse energy on the ablation morphology of groove, and the ablation experimental research of flute with different line overlap rates δ are carried out. The laser scanning confocal microscope is used to observe and analyze the depth, bottom surface roughness and other morphology features of flute. The results show that when the line overlap rate δ satisfies 40%≤ δ ≤80%, with the increase of δ, the depth and sidewall angle of flute decrease, when δ is 40%, the depth, width and sidewall angle of groove is 14.56 μm, 261.8 μm and 59.1°, respectively. The bottom surface roughness decreases as well, when δ is 80%, Ra and Rz reach the minimum of 0.19 μm and 1.23 μm, respectively. The profile fluctuation parallel to scanning speed increases at first then decreases, when δ =80%, Ra′ ≈Ra, Rz′ ≈Rz; The root mean square of bottom surface Sq decreases with the increase of δ, Sq reaches the minimum of 0.16 μm when δ is 80%.