| 题名 | 高功率激光光束质量提升关键因素研究 |
| 作者 | 雷泽民 |
| 文献子类 | 博士 |
| 导师 | 卢兴强 |
| 关键词 | 光束质量 beam quality 光束传输模拟 light propagation simulation 光学元件面形 optical component surface 连续相位板 continuous phase plate 集束聚焦 beam array focus |
| 其他题名 | Research on Key Factors of Improving Beam Quality of High Power Laser |
| 英文摘要 | 高功率激光驱动器是为惯性约束聚变而发展的大型光学装置，在这一大型固体激光装置中，融合了光学，精密机械，自动控制，光学加工等多项顶尖科学技术，其各项指标要求严格，并且随着需求的上升在不断地加强。光束质量作为固体激光器的性能评价要素，在大型驱动装置上有着更为细致严苛的要求。激光器的光束质量受多种因素的共同影响，这其中包括光学传播过程，光学元件质量，系统构型，工作环境及流程管理等。研究提升光束质量要针对这些不同因素采用不同的方法，涉及多个学科，范围广。本论文工作针对光学传播过程和光学元件质量开展研究。因高功率激光驱动器中的光学传播过程复杂且相互影响，所以用计算机进行模拟仿真是必要的研究手段。激光驱动器中的光学元件，其数量巨大且种类繁多。本论文基于模拟仿真的方法主要围绕两类元件面形进行了研究，关注其对光束质量的影响。 本论文研究思路为忽略次要因素，突出主要因素，建立相应的理论模型。理论工具为各种光学理论及相关数值解法。计算工具为可靠性高的软件平台。论文以光学元件面形对光束质量的影响研究为对象，研究了条纹状面形对光束远场的影响规律，提出使用这种元件应满足的限制条件。以提升远场光束质量为目标，提出一种光学衍射方法设计连续相位板，可以将光路中元件引入的相位畸变加入到设计过程中，用于提高连续相位板的整形性能。以提高集束聚焦打靶质量为牵引，对非离轴透镜集束聚焦系统的远场特性进行了研究。另外，还简要研究了振幅型颗粒遮光对光束远场的影响，完成了三款软件的性能测试工作。取得的相关研究成果已在SPIE，Chinese Physics B，中国激光上发表。 对本论文研究工作的详细描述如下： 1. 光学元件的面形是引起光束质量改变的一个重要因素，根据不同的材料，加工方式，元件表面呈现出不同的面形特征。其中由加工引起的条纹状面形是一种对光束质量影响较大的面形，由于其对光束的位相调制类似光栅，所以对光束的远场有明显的影响。基于这一问题，建立了物理模型，模拟计算了调制周期，调制深度等因素对远场的影响规律，并给出了在特定焦斑要求基础上，光学加工所引起的调制周期与调制深度所应满足的条件。还分析了两类条纹状面形元件共同对光束远场分布特性的影响。 2. 连续相位板是高功率激光驱动器的重要光束整形器件之一，其优化设计方法有多种。基于常用的G-S算法，提出了用光学衍射的方法设计相位板，可以将光路中光学元件引入的位相畸变考虑到设计过程中。所设计出的连续相位板即可以满足光束整形的需求，又可以补偿光路中光学元件引入的位相畸变，提高相位板的整形性能。 3. 集束聚焦是目前高功率激光驱动器常用的打靶模式，论文研究了有误差存在时采用非离轴透镜的集束聚焦系统的远场性能。分析了反射镜安装角度误差，透镜安装角度偏差，透镜平移误差，透镜焦距偏差这4项因素对集束系统聚焦性能的影响规律，给出了这些因素对集束聚焦系统远场焦斑的影响程度及对应的控制条件。 4. 研究了振幅型颗粒遮光对光束远场的影响。除灰尘，金属颗粒外，元件表面上的损伤点都可以等效为有遮光效应的“缺陷”，都可以看作振幅型颗粒来研究。研究给出了颗粒粒径，振幅调制度，单表面遮光比等因素对远场的影响规律，对元件表面的洁净度控制有一定参考意义。 5. 介绍了三个软件模块的功能与发展，分别对透镜设计模块，像传递设计模块，频率转换模块进行了测试与功能校核，其中前2个模块可以作为独立的程序运行，功能已经完善。频率转换模块则依赖于主程序框架，目前可以完成基本的运算功能。; High-power laser driver is a large-scale optical device developed for inertial confinement fusion. In this large-scale solid-state laser device, the combination of optics, precision machinery, automatic control, optical processing and many other top science and technology is applied. The indicator requirements of the device are strict, and become strengthened with the rising demand. Beam quality as a solid-state laser performance evaluation element, has more detailed and stringent requirements in a large drive device. The beam quality of the laser is affected by a variety of factors, including optical propagation processes, optical components quality, system configuration, working environments, process management and so on. The research aimed to improve quality of the beam needs different methods for these different factors, involving extensive knowledge within a number of disciplines. The work of this paper is aimed at the optical propagation processes and the quality of optical components. Because the optical propagation processes and the mutual influences in the high power laser driver are complicated, it is necessary to carry out the simulations with the computer. The optical components in the laser drive are large and varied. In this paper, the research based on simulation is mainly focused on the impacts on the beam quality of two kinds of elements. The basic research method of this paper is to ignore the secondary factors, highlight the main factors, and establish the corresponding theoretical model. Theoretical tools are a variety of optical theories and related numerical solutions. The computing tool is a highly reliable software platform. In this paper, the influence of the stripe shape on the far field of the beam was studied, and the limited condition that the component should be satisfied was put forward. In order to improve the quality of the far field beam, an optical diffraction method was proposed to design a continuous phase plate, which could add the phase distortions introduced by component surface shape into the design process to improve the shaping performance of the continuous phase plate. The far field characteristics of the non-off -axis lens cluster focusing system were studied in order to improve focusing performance of cluster system. In addition, the effects of amplitude-modulating particles on the far field of the beam were briefly presented, and the performance testing of three software modules was completed. The relevant results have been published in SPIE, Chinese Physics B and Journal of Chinese Lasers. A detailed description of the work is as follows: 1）The shape of the optical element is an important factor that causes the change of the beam quality. According to the different materials and processing methods, the surface of the element presents different surface features. The stripe shape caused by the optical processing is a kind of surface shape which has a great influence on the beam quality. Because its phase modulation is similar to optical gratings, the stripe shape has a significant influence on the far field of the beam. Based on this problem, a physical model was established to simulate the influence of modulation period and modulation depth on the far field. To meet the prescribed focal spot requirements, the relationship of the modulation period and the modulation depth was also presented. The influence of two kinds of stripe-shaped elements on the far-field distribution of the beam was also analyzed. 2）Continuous phase plate is one of the important beam shaping devices in the field of high power laser driver, and its optimization design method are varied. Based on the conventional G-S algorithm, the method of optical diffraction was proposed to design the phase plate, which can take the phase distortion introduced by the optical elements into the design process. Therefore the continuous phase plate gained by the new method can meet the needs of beam shaping and compensate the phase distortion of the beam, leading to the better shaping performance of the phase plates. 3）The cluster focus is the common targeting mode of high power laser driver. The far-field performance of the cluster focusing system with non-off-axis lens was studied. The influences of the four main factors on the focusing performance of the cluster system were analyzed, including the angle of the mirror installation angle, the lens installation angle deviation, the lens translation error and the lens focal length deviation. The influence degree of these factors on the far field focal spot of the cluster focusing system and the corresponding control conditions were given. 4）The effects of amplitude-modulating particles on the far field of the beam was studied. In addition to dust, metal particles, the damage spots on the component surface can be equivalent to a shading effect "defect". All of them can be seen as the amplitude-modulating particles used to be studied. The influences of particle size, amplitude modulation depth and single surface shading ratio on the far field were discussed, which has reference significance for the cleanliness control of the surface of elements. 5）The function and development of the three software modules are introduced. The lens design module, the transmission design module and the frequency conversion module were tested and verified, respectively. The first two modules can be run as separate programs, and the main functions has been completed. The frequency conversion module, dependent on the main program framework, can run the basic computing functions for now. |
| 学科主题 | 光学工程 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/31001]  |
| 专题 | 中国科学院上海光学精密机械研究所 |
| 作者单位 | 中国科学院上海光学精密机械研究所 |
| 推荐引用方式 GB/T 7714 | 雷泽民. 高功率激光光束质量提升关键因素研究[D]. |
| 个性服务 |
| 查看访问统计 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
修改评论