| 题名 | 超短脉冲激光修复技术研究 |
| 作者 | 熊智敏 |
| 学位类别 | 硕士 |
| 答辩日期 | 2012 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 范薇 |
| 关键词 | 超短脉冲修复，脉宽，FDTD，损伤阈值 |
| 其他题名 | Ultra-short Pulse Laser Ablation Technology Research |
| 中文摘要 | 在高功率激光系统中，激光能量的增加，主要受限于系统中的大口径光学元件的破坏阈值。为了提升整个系统运行效率以及降低运行成本，大口径光学元件的预处理技术以及损伤修复研究引起了比较高的重视。而超短脉冲加工的无热沉积特性，使之成为大口径多膜层元件损伤修复的重要手段。 本论文的主要工作是从影响超短脉冲修复效果的几个因素出发，在理论和实验上分析这些因素对修复效果造成的具体影响，寻找出最佳激光脉冲参数以及合理的修复方式。本论文主要从以下四个方面进行研究分析： 1、从超短脉冲切除的物理机理出发，分析电介质材料内，由多光子电离与碰撞电离产生的自由电子密度分布情况。从而近似计算电介质材料经单发超短脉冲辐照后产生的切除坑形貌。 2、实验分析了脉宽为240ps、35ps、6ps脉冲在1053nm0°与45°高反膜上形成的损伤修复效果。从修复坑形貌、抗损伤阈值、光场调制等方面探究脉冲宽度对修复效果的影响。结果表明，脉冲宽度越小，修复坑内产生的热沉积越少、修复坑形貌越光滑、产生的冷凝沉积物越少、抗损伤性能也就越高。 3、在大尺寸损伤点修复过程中，修复坑的形貌会对修复效果产生很大影响。通过OptiFDTD软件计算证实，修复坑锥角为10°时，1053nm0°高反膜具有最佳的修复效果，而45°高反膜最佳修复形貌为25°锥角。一般情况下，当修复坑锥角小于30°时，损伤修复点都具有比较好的抗损伤效果。 4、探究不同能量的40fs脉冲在1053nm高透膜上损伤形貌，在理论和实验上得出，在脉冲叠加程度为60%情况下，损伤修复坑具有最平坦的修复面型。 单点损伤修复形貌与材料抗损伤阈值有着密切联系。通过分析不同能量下的单脉冲修复尺寸可以计算出材料在不同脉宽下的抗损伤阈值。计算得出，1053nm0°高透膜在40fs脉冲下的损伤阈值约为3.31 。从而为多脉冲扫描修复过程中确定单脉冲能量、扫描速度以及扫描次数提供参考。 |
| 英文摘要 | With the development of laser technology, the idea of inertial confinement fusion driven by laser would be possible. In high power laser systems, optical components can be easily breakdown under the high power laser irradiation. So the overall system’s operating efficiency will be reduced and the operating costs will be increased. No heat deposition characteristics of the ultra-short pulse processing, makes it an important means of multi-layer components damage repair. The main work of this thesis are discussing the impact factors on the short pulse laser ablation effect and investiging the optimal laser pulse parameters for componet damage site repairement. The thesis is divided into four parts: (1) Starting from the physical mechanism of ultra-short pulse ablation, the distribution of freedom electron density within the dielectric material generated by multi-photon ionization and collision ionization is analyzed. The ablation pits morphology generated by single ultra-short pulse irradiation on the dielectric material surface is simulated. (2) The damage site repairing effects on surface of 0 and 45 high reflective films(1053nm) irradiated by 240ps, 35ps, 6ps pulses are analyzed. The results show that the shorter the pulse width, the less deposition and the smoother the repair pits morphology and the better damage resistance property will be obtained. (3) For large area damage defects repairment, the morphology of the ablation pits is one of the key factors. Confirmed by OptiFDTD software, 0 and 45 high reflection films(1053nm) have the best ablation pits morphology when cone angle is 10 and 25 seperately. Generally, when the repair pit cone angle is less than 30, the repair pit has a better resistant damage effect. (4) The influence of pulse energy on the repairment morphology of the damge site is testified. According to the single shot damage morphology with different laser energy, the best scanning speed and the best overlapping was determined. The least surface roughmess was obtained with 60% pulse overlap. The repair pits morphology was also decided by the dielectric damage threshold, of which the threshold of 0 degree high reflection film(1053nm) is caculated and testified to be equal to 3.31 . All the results would provide a reference for deciding the pulse energy, scanning speed and scanning times in ablation experiments. |
| 语种 | 中文 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16716]  |
| 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 | 熊智敏. 超短脉冲激光修复技术研究[D]. 中国科学院上海光学精密机械研究所. 2012. |
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