飞秒激光加工高深径比微孔的研究

发布时间：2018-02-03 01:28

本文关键词： 双温模型多脉冲激光烧蚀高深径比　出处：《上海交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：过去二十年以来,由于飞秒激光与材料相互作用有着能量快速沉积和减小不必要的热损伤区域等优点,飞秒激光烧蚀深小孔加工得到了人们的许多关注和研究。受到传统高斯光束瑞利长度的限制,实现高深径比的小孔是微孔加工的瓶颈。在我们已经在之前的模型中研究了单脉冲激光烧蚀金属铝的双温模型。但是,对于加工高深径比的小孔,单脉冲双温模型并不能给我们提供有效的数据,因此我们提出了改进的三维双温模型用于研究多脉冲飞秒激光烧蚀小孔。我们计算了多脉冲激光烧蚀阈值并研究了激光能流密度、脉冲次数、腰斑半径等参数对小孔形貌的影响规律,为微加工实现提供理论依据。得出激光能流密度和脉冲次数主要影响烧蚀小孔的深度,对孔径的影响作用比较缓慢。而腰斑半径则主要影响烧蚀小孔的孔径大小,几乎成线性的关系,对烧蚀小孔的深度则没有影响。另外,本文还进行了飞秒激光烧蚀金属铝和聚苯乙烯薄膜的实验,探讨了真空度对小孔溅射物的影响,利用定制的真空腔环境使得飞秒激光烧蚀小孔周围溅射物减少,并计算了多脉冲烧蚀金属铝的烧蚀阈值,与模拟结果大致相同。还在研究了激光能流密度和脉冲次数对小孔深径比的影响。在飞秒激光烧蚀聚苯乙烯薄膜实验中,研究了激光重复频率、材料表面水膜和腰斑聚焦位置对小孔形貌的影响。以及激光能量密度和脉冲次数等各激光加工参数对小孔深径比的影响。最后,理论分析了平凸锥透镜产生贝塞尔光束的性质,实验上采用锥角1°的平凸锥透镜搭建了贝塞尔光束飞秒激光微加工平台,为后续加工出高深径比的小孔做好准备。
[Abstract]:Over the past two decades, the femtosecond laser interaction with materials has the advantages of rapid energy deposition and the reduction of unnecessary thermal damage zones. The fabrication of deep holes by femtosecond laser ablation has attracted much attention and research, which is limited by the Rayleigh length of traditional Gao Si beam. The hole with high aspect ratio is the bottleneck of microhole machining. In the previous model, we have studied the double temperature model of single pulse laser ablation of metal aluminum. However, for the processing of small hole with high depth to diameter ratio, The monopulse double temperature model can't provide us with valid data. Therefore, an improved three-dimensional dual-temperature model is proposed to study the ablation of holes by multi-pulse femtosecond laser. We calculate the threshold of multi-pulse laser ablation and study the laser energy flow density and pulse number. The influence of the parameters such as the waist spot radius on the pore morphology provides a theoretical basis for the realization of micromachining. It is concluded that the laser energy flow density and the number of pulses mainly affect the depth of the ablation hole. The effect on pore diameter is slow, while the radius of waist spot mainly affects the aperture size of the ablative hole, which is almost linear, but has no effect on the depth of the ablated hole. The experiments of femtosecond laser ablation of aluminum and polystyrene films are also carried out. The effect of vacuum on the microporous sputtering is discussed, and the amount of sputtering around the holes is reduced by using the customized vacuum cavity environment. The ablation threshold of multi-pulse ablative aluminum is calculated, and the results are approximately the same as the simulation results. The effects of laser energy flux density and pulse number on the ratio of depth to diameter of small holes are also studied. In the experiment of femtosecond laser ablation of polystyrene films, The effects of laser repetition rate, water film on the surface of the material and the focusing position of the waist spot on the morphology of the pore are studied. The effects of laser processing parameters such as laser energy density and pulse number on the ratio of depth to diameter of the small hole are also studied. The properties of Bezier beam produced by flat convex conical lens are analyzed theoretically. In the experiment, a beisel beam femtosecond laser micromachining platform is built by using a flat convex conical lens with a cone angle of 1 掳, which is ready for the subsequent fabrication of small holes with high aspect ratio.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN249

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