【作者】 胡永军；

【导师】 于起峰； 伏思华；

【作者基本信息】 国防科学技术大学 ， 光学工程， 2010， 硕士

【摘要】 高能激光器非稳谐振腔的准直度直接影响其输出光束质量以及输出功率的稳定性,因此在每次运行之前均需要对腔镜进行准直调校。激光器非稳谐振腔导引光近场光斑呈现干涉条纹分布,且其分布形状与腔镜失调量之间存在直接联系,目前广泛采用的人工调腔方法正是利用这一点进行调腔。但是工程应用中该方法不可避免的存在调腔精度受限、耗时长、可重复性差等缺点。针对此问题,本文提出了基于条纹骨架线处理的调腔方法和基于条纹图灰度投影的调腔方法并进行了实验研究。本文在系统介绍现有的调腔方法的基础上,针对高能激光器中常用腔型之一的正支共焦非稳腔,分析了其结构特点和失调特性,讨论了导引光近场干涉条纹的形成机理以及干涉条纹分布与谐振腔失调量之间的关系,提出了基于条纹骨架线处理的调腔方法和基于条纹图灰度投影的调腔方法,并建立了评价腔镜准直度的客观判据,编写了腔镜准直度分析软件,搭建了基于条纹骨架线处理方法和基于条纹图灰度投影方法的调腔实验平台。结果表明,基于条纹图灰度投影的调腔方法在图像处理的速度和精度上都明显优于基于条纹骨架线处理的调腔方法,能做到实时处理图像,图像分析计算误差在0.1个像素之内。另外,实验也证明:基于条纹图灰度投影的调腔方法可以有效提高现有人工调腔方法的精度,使调腔精度优于15.7μrad。更多还原

【Abstract】 The cavity mirrors alignment of the unstable resonator in a high-energy laser has direct influence over the quality of its output beams and the stability of its output power. Therefore, it is necessary to align the cavity mirrors before each operation. The near-field patterns of the guided light of the unstable resonator present themselves in the form of interference fringes. And their distribution shape has some direct relationship with the cavity mirrors’ misalignment. Based on this, the artificial cavity mirrors alignment has been realized and applied widely. However, the existing approach has inevitable disadvantages of limited alignment precision, long time consumption, and poor repeatability in actual construction. To solve these problems, a resonator alignment method based on fringe skeleton processing and a resonator alignment method based on the fringe pattern grey projection were proposed,and also the experimental study were carried though.In this thesis,based on a systematic introduction of existing cavity mirrors alignment methods, we focus on positive-branch con-focal unstable resonator, which is one of the most common resonators of high energy-laser as an example, analyzed its structural features and offset characteristics, and further discussion of the output near-field interference fringes of guide light’s formation mechanism and the relationship between the distribution shape of interference fringes and the offset amount of cavity mirrors, proposed a resonator alignment method based on fringe skeleton processing and a resonator alignment method based on the fringe pattern grey projection, and also established corresponding objective criteria of cavity mirrors alignment degree, wrote the cavity mirrors alignment degree analysis software, built experiment platform of the two cavity mirrors alignment methods. Results show that the resonator alignment method based on the fringe pattern grey projection’s image processing speed and processing accuracy are much better than the resonator alignment method based on fringe skeleton processing, The former method can do real-time image processing and analysis, it’s calculation error is less than 0.1 pixel. In addition, the experiments also prove that: with the aid of fringe pattern projection method, the artificial cavity mirror alignment method can effectively improve it’s alignment accuracy, To achieve an accuracy better than 15.7μrad.更多还原