第 1 页 摘要 近年来，由于飞秒激光烧蚀透明材料时所独有的特性，使得飞秒激光对透明材料的微 加工研究成为了人们广泛关注的焦点，但多集中于研究与玻璃、石英、晶体等一些硬质材 料相互作用，而对传统的容易解理材料，如冰洲石、云母晶体等的损伤阈值和微加工研究 还鲜有报道。尤其是云母材料切割、钻孔加工技术还存在诸多的技术问题难以解决，严重 制约了此优质光学双折射材料的利用。因此，研究飞秒激光与云母晶体的相互作用有着非 常重要的实际意义，这一研究项目也得到了省主管部门的资金支持。 本报告对飞秒激光微加工云母晶体进行了部分的理论与实验研究工作，主要包括以下 几个部分的内容， （1）介绍了飞秒激光与透明材料的微细加工研究现状，总结探讨了飞秒激光烧蚀透 明材料的物理机制，其中，重点讨论了雪崩电离及多光子电离的过程，理论分析了激光脉 冲烧蚀透明材料的烧蚀阈值、烧蚀深度与脉宽和光子能量之间的关系。 （2）实验测量了飞秒激光烧蚀不同厚度的云母材料的损伤阈值，研究了材料厚度与 损伤阈值的关系，验证了飞秒激光与透明材料相互作用的多光子电离损伤机制，得出了损 伤阈值与材料的厚度无关，而只与材料本身的性质有关的结论，并为飞秒激光微加工透明 晶体的研究打下了基础。 （3）利用飞秒激光对云母晶体进行微加工可行性实验研究，并尝试了制备微型实验 器件的研究工作；针对云母材料孔加工技术，详细比较了飞秒激光孔加工与机械孔加工这 两种工艺之间的优劣性。 本文的主要创新点如下， （1）首次提出通过云母晶体的飞秒激光能量透射比的迅速变化来判断材料损伤阈值 点的观点，并利用这一方法测量了厚度在45μm～138μm内的云母晶体的损伤阈值。实验发 现，在特定脉宽的飞秒脉冲激光作用下，其损伤阈值与材料的厚度无关，而只与材料本身 的性质有关。 （2）研究了飞秒激光对云母材料孔加工工艺的可行性，实验结果表明，其具有传统 的机械孔加工云母材料所无可比拟的优势。成功用飞秒激光加工出了直径小到了几百微米 的微小型云母波片，为将来云母材料微型化的应用提供了重要的借鉴意义。 关键词，激光技术；飞秒激光；云母晶体；损伤阈值；微加工摘要 第 2 页 Abstract Recently, because of the unique characteristics of femtosecond laser ablate transparent materials, using femtosecond laser to transparent materials become the focus of people widely concern about. People are more focused on researching the interaction between femtosecond laser and some materials such as glass, quartz, crystal. Research on the damage threshold and micro-machine of traditional crystals such as Iceland spar, mica, has been little report. And particularly there are many technical issues of Mica material cutting and drilling, which severely constrain this high quality optics of birefringent material to use. So, research the interaction of femtosecond laser and mica crystal has very important practical significance. This research project also has received financial support from the provincial authorities. In this dissertation, parts of theoretical and experimental studies on using femtosecond laser to micro-machine mica crystal are presented. The main contents are classified as follows. (1) The research status of using femtosecond laser to micro-machine transparent materials is introduced briefly. The physical mechanism of transparent materials ablated by a femtosecond laser pulse is summarized, which focused on the ionization processes of multi-photon ionization and avalanche ionization. The relation between damage threshold and laser pulse duration, photon energy is studied. (2) Damage thresholds of different thickness of the mica materials are measured under the femtosecond laser. The relationship between thickness of material and damage threshold is studied. Multi-photon ionization mechanism of the femtosecond laser interact with transparent materials is verified, which is not directly related to the thickness of the sample, and only the nature of the material itself is related. These laid foundation for researching the femtosecond laser micro-machine mica crystal. (3) The research of experiment that using femtosecond laser to micro-machine mica crystals, attempting to make some microscale experiment devices. A detailed comparison of advantages and disadvantages of the process between the femtosecond laser hole machining and the traditional mechanical hole machining. The main innovations in this dissertation are classified as follows. (1) The view of damage threshold point is judged by the emergence of the sudden change in transmittance is proposed in first time. According to this method, damage thresholds of mica crystal with thickness ranged from 45μm to 138μm are measured accurately under the femtosecond laser. The result indicates that damage threshold of mica irradiated by femtosecond laser with a specific pulse width is not directly related to the thickness of the sample, and only the nature of the material itself is related.(2) The process of using femtosecond laser to machine hole in the mica materials are studied simple. The results of experimental show that it has incomparable advantages compared to the process of traditional mechanical hole machining.Using femtosecond laser to the machine micro-mica wave plates with diameter as short as a few hundred micrometers. And this provides an important reference for the future application of the miniaturization of the mica material. Key words: Laser technique; femtosecond laser; Mica crystal; Damager threshold; Micromachining目录 第 1 页 目录 第一章 绪论..............................................................................................1 1.1 飞秒激光加工的特点...................................................................................... 1 1.2 飞秒激光加工透明材料研究现状与进展...................................................... 3 1.3 本报告的主要内容.......................................................................................... 5 第二章 飞秒激光与透明材料相互作用的机制与理论分析.................6 2.1 飞秒激光烧蚀透明材料的物理机制............................................................. 6 2.1.1 雪崩电离............................................................................................... 6 2.1.2 多光子电离........................................................................................... 7 2.2 飞秒激光烧蚀电介质材料的理论分析......................................................... 8 2.3 本章小结....................................................................................................... 10 第三章 飞秒激光微加工实验系统........................................................11 3.1 飞秒激光器的工作原理 ........................................................................................11 3.2 三维数控高精度微加工实验平台............................................................... 13 3.3 微加工系统光路装置及其工作原理 ................................................................. 14 3.4 本章小结 ................................................................................................................ 15 第四章 飞秒激光烧蚀云母晶体的实验研究 .......................................16 4.1 云母晶体的物理特性与应用....................................................................... 16 4.2 飞秒激光烧蚀云母晶体的损伤阈值分析................................................... 17 4.2.1 损伤阈值的确定方法................................................................................ 17 4.2.2 损伤阈值的测量................................................................................. 18 4.2.3 损伤阈值的误差来源分析.................................................................. 19 4.3 本章小结....................................................................................................... 20 第五章 飞秒激光对云母晶体微加工实验研究 ...................................21目录 第 2 页 5.1 飞秒激光微加工云母晶体............................................................................ 21 5.1.1 实验装置.............................................................................................. 21 5.1.2 钻孔..................................................................................................... 22 5.1.3 微型云母波片的制备......................................................................... 23 5.2 与传统孔加工技术的优劣比较................................