倍频用大口径KDP晶体精密安装工艺研究
文献类型：学位论文
| 作者 | 沈健 |
| 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 | KDP晶体 有限元方法 面形质量 准运动耦合 定位精度 |
| 其他题名 | Research on Precision Installation Process of Large-aperture KDP Crystal for Frequency Conversion |
| 中文摘要 | 在惯性约束核聚变装置终端光学组件中，KDP晶体作为频率转换元件具有口径大、厚度小的结构特点，在重力作用下容易变形，引起相位失配，导致频率转换效率的下降。此外，晶体与光束的之间夹角也需要严格控制，以保证相位匹配条件，而这需要对晶体的定位精度进行设计，否则也会降低频率转换效率。因此，研究倍频用大口径KDP晶体的精密安装工艺，使之在装夹机构夹持力的作用下能保持良好的面形质量和应力分布状态，并且能够保证足够高的快速安装更换定位精度，这对于高功率激光系统获得高质量光束、高的维护效率具有重要的意义。 本文基于弹性薄板变形理论，建立边界约束条件下晶体形变的理论公式并计算因重力作用导致的变形量，同时建立了力学参数对晶体性能的影响关系。 本文基于非理想接触面条件下分析了面接触装夹方案的晶体面形质量，提出了改善的点接触装夹模型方案，通过有限元方法分析了该装夹方式对晶体变形、应力、折射率变化等方面的影响，并采用优化算法对接触点的位置进行优化，根据优化结果设计点接触模型结构，并进行装夹测试，测试结果表明该晶体夹持方案能有效改善晶体的面形质量。 除了装夹机构对晶体面形的影响外，晶体安装的位置精度也会影响频率转换效率。本文针对终端光学组件中晶体安装机构的要求，研究了准运动耦合机构（Quasi-Kinematic Coupling, QKC）的定位方案可行性。分析了准运动耦合机构的特点以及影响定位精度的因素，建立了准运动耦合机构互换性误差的几何模型，并推导了其数学表达式，然后通过蒙特卡洛方法对结构的定位精度进行了计算与分析。将设计的方案制作了实物模型，采用三坐标测量仪中对定位精度进行了测试。 |
| 英文摘要 | In the final optics assembly (FOA) of the Inertial Confinement Fusion (ICF) device, KDP crystal is used as frequency converter. Because it has a structural characteristic of large aperture and small thickness, the crystal will be easily deformed by gravity, which may induce the phase mismatch, resulting in the decrease of frequency conversion efficiency. In addition, the angle between the crystal and the beam also need to be strictly controlled to ensure the phase matching condition. And this need to design the positioning accuracy of the crystal, otherwise it will reduce the frequency conversion efficiency. In order to obtain high beam quality, it is important to do a research on precision installation process of large-aperture KDP crystal. So that the crystal can keep a good surface quality and stress distribution with the clamping mechanism, and maintain a high positioning accuracy with precision positioning mechanism. In this paper, based on the theory of elastic thin plate deformation, the theoretical formula of the crystal deformation under the condition of boundary constraints is established and the deformation caused by gravity is calculated. And the influence of the mechanical parameters on the crystal properties is established. The surface quality of the crystal under the condition of non-ideal contact surface is studied. Based on the analysis result, an improved point contact clamping scheme is put forward. The effect of the mounting configuration on the deformation, stress and refractive index change of the crystal is analyzed by means of finite element methods (FEM).The position of the loading plates is optimized by adaptive single-objective algorithm. Based on the result of optimization, the structure scheme of point contact model is designed. A physical model is produced and tested. The test result shows that the mounting configuration is able to improve the surface quality of the crystal. The position accuracy of the frequency converter also affects the frequency conversion efficiency. Quasi-kinematic coupling (QKC) is studied according to the requirements of the crystal mounting mechanism in the final optics assembly. The structural characteristics and the factors that affect the positioning accuracy are analyzed. The geometric model of QKC structure is established, and its mathematical expression is derived. Then, the positioning accuracy of the structure is calculated and analyzed by means of Monte Carlo method. A physical model is produced and its positioning accuracy is tested with three-coordinates measuring machine. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16974]  |
| 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 | 沈健. 倍频用大口径KDP晶体精密安装工艺研究[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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