溶胶-凝胶膜光学表面激光清洗工艺研究

为了解决光学元件表面的颗粒污染问题,在单发次激光干式清洗的基础上,提出了气流置换系统辅助的激光清洗方法,使用波长为355nm的Nd∶YAG激光器,针对镀溶胶-凝胶SiO 2薄膜熔石英光学表面粒径为1μm^50μm的典型SiO 2颗粒污染物,进行了理论分析和清洗实验,取得了可用于激光清洗的工艺参量。结果表明,对于镀溶胶-凝胶膜熔石英样品的单发激光干式清洗,最佳激光能量密度为2.29J/cm 2,与未镀膜石英的激光清洗工艺参量存在一定差异;在最佳工艺参量下,单发次激光清洗对于粒径1μm以上的SiO 2颗粒清洗效果明显,移除率可达82.96%;当污染密度过高时会导致清洗效果的减弱及对基底的损伤,而气流置换系统辅助的激光清洗方法可进一步增强对光学表面颗粒污染的去除效果。该研究对大型高功率固体激光装置中的光学元件在线清洗及清洗装备的设计具有重要的研究意义与实用价值。

Study on laser cleaning process of sol-gel film optical surface

In order to solve the problem of particle contamination on the surface of optical elements, on the basis of single laser dry cleaning, laser cleaning assisted by air displacement system was proposed. Nd:YAG laser with 355nm wavelength was used. Typical SiO₂ pollutant particulate with optical surface diameter of 1μm~50μm for sol-gel SiO₂ thin film fused silica was theoretically analyzed and cleaning experiments were carried out. The process parameters for laser cleaning were obtained. The results show that, for single crystal laser dry cleaning of sol-gel membrane fused silica samples, optimum laser energy density is 2.29J/cm2. The process parameters of laser cleaning are different from those of uncoated quartz. Under the optimum technological parameters, the effect of single laser cleaning on SiO₂ particles with particle size more than 1μm is obvious. The removal rate is 82.96%. Excessive contamination density will weaken the cleaning effect and damage the base. Laser cleaning assisted by air displacement system can further enhance the removal effect of particle contamination on optical surface. This research has important research significance and practical value for on-line cleaning of optical components and the design of cleaning equipment in large-scale high-power solid-state laser devices.