高功率激光驱动器有机污染物监测技术及损伤研究
文献类型：学位论文
| 作者 | 朱政豪 |
| 学位类别 | 硕士 |
| 答辩日期 | 2016 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 刘志刚 |
| 关键词 | 高功率激光 有机污染物 激光诱导损伤 分子态污染物 |
| 其他题名 | Detection of Organic Contamination and Laser Induced Damage in High Power Laser System |
| 中文摘要 | 光学元件的损伤限制高功率激光驱动器负载能力提升，阻碍了惯性约束核聚变的发展。其中，有机物对光学元件的污染是降低光学元件损伤阈值，诱导光学元件发生损伤的重要原因。研究高功率激光器中有机污染物诱导光学元件损伤的特性，监测系统中污染物在光学元件表面的沉积，有利于有机物污染源的控制，改进装置洁净环境，避免光学元件损伤的发生，增加光学元件的使用寿命，对提高负载能力和运行稳定性具有现实意义。 本论文主要包括激光与聚合物材料相互作用、有机污染物诱致光学元件损伤和分子态污染物在光学元件表面沉积监测技术研究等三部分，具体研究内容如下： 一、激光与聚合物材料相互作用。本论文涉及高功率激光器中常用有机物聚四氟乙烯、真空橡胶、丁腈橡胶、硅橡胶等的基本特性以及激光与聚合物的相互作用。分别对这些常见有机物进行了纳秒（6ns，1064nm）和皮秒（9ps，1053nm）激光损伤实验，获得了不同材料的损伤形貌、损伤阈值、烧蚀深度和烧蚀速率。实验结果表明聚四氟乙烯具有较高的抗损伤能力，对有机物材料的选择和使用范围有指导性作用。 二、有机污染物诱致光学元件的损伤。有机污染物与激光相互作用是系统中重要的污染物来源，其产生的污染物颗粒或者气溶胶会影响装置的洁净度，诱导光学元件损伤。本论文简述了光学元件损伤机理和测试方法以及颗粒污染物、膜状污染物诱导光学元件损伤模型。实验研究了皮秒激光（9ps，1053nm）辐照下，PETG 颗粒物污染物诱致光栅表面损伤特性。实验结果表明，当激光通量为 2.27 J/cm2时，测试的所有尺寸的 PETG 颗粒（>10μm）被激光辐照后，光栅表面均发生不同程度的损伤；颗粒尺寸越大，损伤区域越大。但随着激光通量的降低，诱致光栅损伤的 PETG 颗粒临界尺寸增加。获得了光学表面颗粒污染物允许极限尺寸与负载通量的关系曲线，有助于皮秒拍瓦装置的洁净控制。 三、光学元件表面分子态污染物沉积技术研究。本文简述了石英晶体微量天平和微纳光纤传感器的测试原理，根据视角因子等分模型对石英晶体微量天平和微纳光纤传感器样机进行了对比测试，比较了两种测试方法的特点。此外，还开展了分子态污染物在镀有 sol-gel 膜微纳光纤沉积特性的研究。实验结果表明，沉积在微纳光纤上的污染物质量与腔内污染物的浓度分布为非线性关系，有机污染物浓度越高越容易在微纳光纤表面沉积；镀 sol-gel 膜的微纳光纤比裸光纤更容易吸附污染物。 |
| 英文摘要 | Optical damage is the main issue that limits the high fluence operation of high power laser system. Organic contamination is one of the main pollution sources that reduce the optical damage threshold and induce damage of optics in high power laser facility. In order to reduce the organic contamination, it is practically significant to study the generation and detection of organic pollutants as well as contaminant-induced optical damage. It is crucial to improve the damage resistance of large optics and operating stability for high power laser system. The thesis consists of three parts reviewed as follows: 1. Laser damage of polymer materials. We review the physical features of common used polymer materials such as polytetrafluoroethylene, vacuum rubber, nitrile rubber and silicone rubber as well as the theoretical model of laser interaction with the polymer. For each of these materials, damage experiment by nanosecond pulsed laser(1064nm, 6ns) and picosecond pulsed laser(1053nm, 9ps) are carried out. The damage morphologies, damage thresholds, ablation rates and ablation depths of these materials are investigated. The experimental results show that polytetrafluoroethylene has the highest damage threshold, which gives guidance for the use of organic materials in high power laser system. 2. Laser interaction with polymers is the main pollutant source which can produce lots of particles or aerosols to contaminate the optics. We describe the damage mechanism and models of optics. We experimentally study the polymer particle induced damage of compression grating irradiated by picosecond pulsed laser at 1053nm. When laser fluence is larger than 2.27 J/cm2, the grating surface is always damaged regardless of the size of PET-G particles (larger than 10 μm). The larger the particle size, the greater the damage area. With the laser fluence decreases, the PETG particle size that induced damage of grantings is increased. Finally we get the relation between the laser fluence and the permitted size of particles on optical surface. 3. In order to monitor the volatilization and deposition of organic contaminants on optics surfaces, online detection of airborne molecular contaminant is investigated based on quartz crystal microbalance(QCM) and optical microfiber(OM). The detection characteristics of QCM and OM are experimentally compared in vacuum chamber based on the flow distribution model. The deposition characteristic of airborne molecular contaminant on sol-gel optical microfiber film is also studied. The experimental results show that the more the density of airborne molecular contamination is, the more it deposits on the optics. Sol-gel film is more efficient to absorb pollutants than the bare optical fiber. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16995]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 朱政豪. 高功率激光驱动器有机污染物监测技术及损伤研究[D]. 中国科学院上海光学精密机械研究所. 2016. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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