脉冲群预电离CO_2脉冲激光器及激光束聚焦特性研究
文献类型：学位论文
| 作者 | 李现勤 |
| 学位类别 | 博士 |
| 答辩日期 | 2001 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 程兆谷 |
| 关键词 | 预电离 脉冲群开关技术 非自持放电 大气传输 聚焦特性 飞行光学 自适应 |
| 中文摘要 | 本论文基于两项国家自然科学基金资助项目：“脉冲群开关预电离技术实现巨脉冲CO_2激光输出的研究”(批准号：60078017)和“部分相干光聚焦特性的理论与实验研究”(批准号：69978022)。主要工作是：在独特的预电离针管条电极结构上利用脉冲群预电离开关技术实现脉冲CO_2激光输出。本工作在国际属首创，已申请发明专利一项，实用新型专利一项(已授权)。相关文章已被IEEEJ．Quant．Electron．(SCI一区收录的期刊)录用，审稿人都给予了很高的评价，认为该研究成果在创新和应用方面有重要贡献，对该领域内的相关人员有重要意义，将引起专业人员的很大兴趣。本论文的工作还包括飞行光学以及激光在大气中传输的若干问题。该项成果在日本大阪和美国圣达菲先后召开的两次SPIE国际会议上分别发表了特邀报告，并在《中国科学》A辑上发表。该项研究对于飞行光学激光加工、光学飞行器、大型激光工程空间滤波器等应用领域具有重要研究价值。本文介绍了气体流动CO_2激光器及脉冲CO_2激光器的各种应用，概括了各种脉冲电功率注入方法，对比分析了加拿大、印度和上海光机所横流CO_2激光器的不同点。扼要介绍了气体放电中的辉光放电与非自持放电的特性。在此基础之上，本论文提出，采用独特的电极结构，来实现脉冲CO_2激光输出。论文重点介绍了独特的预电离针管条电极结构及其优点。激光器主放电是由脉冲预电离提供初始电子的非自持特性的辉光放电，利用该特性，可实现预电离脉冲群开关调制的主放电电功率注入。文中给出了预电离脉冲群和主放电的电压电流测量波形、脉冲激光输出波形，并进行了分析。文中还提出了高功率脉冲激光能量的衰减方法：偏振衰减和部分反射光衰减。论文利用几种不同波长的激光束，研究了大气湍流与热晕对于长距离传输激光束聚焦特性的影响。光束质量BQ与光束漂移量的理论与实验值基本一致。论文还提出应用自适应z形折叠镜来解决飞行光学聚焦特性的问题。 |
| 英文摘要 | This paper is based on two projects supported by the National Natural Science Foundation of China. One is "Study on the technique of pulsed burst-mode switch to realize huge pulsed CO_2 laser output"(Grant No. 60078017), the other is "Theoretical & experimental study on the focus characteristics of partially coherent light"(Orant No. 69978022). The main work of this paper is using the technique of pulsed burst-mode switch to realize the pulsation of CO_2 laser power on the unique preionized pin tube-plank electrode structure. This work is original internationally. A patent of invention has been applied, and a patent of utility rnodel has been applied and authorized. The correlative paper has been accepted by IEEE J. Quant. Electron., which is a journal of the first area in SCI index. All the reviewers evaluated the paper highly. They considered the paper make a significant contribution in terms of novelty or application, be of interest to a wide range of people, and be of high interest to a small range of people working in the field. The works in this paper also include the problems of the flying optics and the focus characteristics of the laser beam for long distance propagation in atmosphere. Two invited papers have been published in the SPIE conferences (one is SPIE's Inter-national Forum on Advanced High-Power Laser and Application, Osaka, Japan, the other is SPIE's International Symposium on High-Power Laser Ablation 2000, Santa Fe, USA.). The paper has also been published in Science in China (A). The research will be of high interest and value to the flying optical laser manufacturing, lightcraft, and spatial filter in the big laser engineering. In this paper, we introduce the gas flow CO_2 lasers and the various applications of the pulsed CO_2 lasers. The various methods for the pulsed electrical power input are summarized, the differences of the high power transverse CO_2 lasers in Canada, India and China are presented in detail, and the glow discharge and the nonself-sustained discharge are simply analyzed. Based on the techniques, the preionized pulse-train switched technique is developed to achieve pulsed laser outpnt using a tmique electrode structure. The unique preionized pin tube-plank electrode structure and its merits are emphasized. The main discharge of the laser is the nonself-sustained glow discharge whose initial electrons are provided by the preionization. Taldng advantage of the characteristics of the nonself-sustained glow discharge, we can achieve the pulsed power input of the main discharge. The voltage and the current waveforms of the preionized pulse-train and the main discharge, and the waveforms pulsed laser output are put emphasis on and the analyses are given. Two attenuation methods for the high power pulsation are discussed: the polarized attenuation method and the partial reflex attenuation method. In this paper, the influence of atmospheric turbulence and thermal blooming on focus characteristics of laser beam is given for several typical lasers with different wavelength. The calculations of the BQ and the excursion coincide with the experimental result. The self-adaptive Z-shaped system is used to solve the flying optics problem. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15313]  |
| 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 | 李现勤. 脉冲群预电离CO_2脉冲激光器及激光束聚焦特性研究[D]. 中国科学院上海光学精密机械研究所. 2001. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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