目的 研究激光平滑光学元件的工艺，探索使用CW（连续）CO2激光器对熔石英光学元件表面进行平滑处理时，当激光束功率、束斑尺寸一定的情况下，不同的扫描速度对平滑后熔石英元件表面粗糙度的影响规律。方法 用仿真结合实验的方式进行了研究。使用有限元仿真模型对激光功率为25 W，作用斑点为短轴2 mm、长轴3 mm的椭圆斑的激光加工模型进行了仿真，得到了不同扫描速度下激光束作用于熔石英表面的温度场及对应的稳定温度。通过定点照射实验验证了温度仿真结果的准确性，并进行了扫描速度为0.04、0.1、0.2、0.35、0.5 mm/s的单因素实验，使用原子力显微镜检测平滑实验前后的熔石英表面粗糙度，得到了粗糙度与激光扫描速度之间的关系。结果 激光功率为25 W时，5种扫描速度对应的稳定温度都分布在熔石英材料的熔点以上。5种扫描速度下平滑后的熔石英表面粗糙度都明显降低，在扫描速度为0.1 mm/s的情况下，取得了将熔石英表面粗糙度由初始的62.55 nm降低至6.17 nm的平滑效果。结论 激光平滑过程中，当激光功率、激光斑尺寸一定时，存在一个最佳的扫描速度，可以使加工表面的粗糙度降低至光学表面的要求。

The work aims to study the technology of smoothening the fused silica optical elements and explore the influence of different scanning velocities on the surface roughness of smoothed fused silica optical elements when CW CO2 laser is used to smoothen the fused silica optical elements under the fixed laser power and beam size. The study was carried out by simulation and experiment. A finite element model was used to simulate the laser processing model with a laser power of 25 W and an elliptical spot with a minor axis of 2 mm and a major axis of 3 mm. The temperature field and corresponding stable temperature of laser beam acting on the surface of fused silica under different scanning speeds were obtained. The accuracy of temperature simulation model was verified by fixed-point irradiation experiment, and single factor experiments with scanning speeds of 0.04 mm/s, 0.1 mm/s, 0.2 mm/s, 0.35 mm/s and 0.5 mm/s were carried out. Atomic force microscope was used to detect the surface roughness of fused silica before and after the smoothing experiment, and the relationship between roughness and laser scanning speed was obtained. When the laser power was 25 W, the stable temperature corresponding to the five scanning speeds was all distributed above the melting point. The surface roughness of the fused silica after smoothing at five scanning speed was significantly reduced, and the smoothing effect of reducing the initial surface roughness of the fused silica from 62.55 nm to 6.17 nm was obtained at a scanning speed of 0.1 mm/s. When the laser power and laser spot size are constant, there is an optimum scanning speed to reduce the roughness of the machined surface to the optical surface.