【作者】 王薇；

【导师】 陈怀新；

【作者基本信息】 四川大学 ， 光学， 2005， 硕士

【摘要】 在驱动聚变的高功率激光系统中,激光束的质量控制是确保激光系统安全运行,激光束能量有效提升的重要前提之一。其中,激光中频段的小尺度波前畸变的探测与控制是波前质量控制的重要研究课题。本文采用阵列菲涅耳波带片作为波前传感器,对激光小尺度波前畸变探测误差和如何提高探测精度进行了理论分析与光学实验研究,得到的主要研究成果如下: 一、根据哈特曼—夏克波前传感原理,采用振幅型阵列菲涅耳波带片作为波前传感器,分析了菲涅耳波带片的波前测量灵敏度和测量动态范围,实验研究了菲涅耳波带片的聚焦特性。 二、分析了光源高斯随机噪声和波带片阵列结构对激光波前恢复的影响,为提高激光小尺度波前探测与补偿能力提供了系统设计和实际操作的参考。 三、通过五种滤波光斑图抑噪方法的分析比较,提出采用两种非线性滤波的光斑图去噪方法。根据图像处理中插值理论,提出基于双立方插值处理的光斑质心探测方法,极大地提高了质心探测精度。 四、提出另一种提高质心探测精度的新方法---基于优化的探测窗口的光斑质心探测方法,改进质心计算算法,提高了探测波前的重建精度。 五、针对长焦距透镜和平晶玻璃所引入的波前畸变,分别采用双立方插值法、基于优化的探测窗口法进行激光小尺度畸变波前探测与恢复的实验研究,初步证实了本文提出方法对激光小尺度畸变波前探测的有效性,并给出了波前探测与恢复精度。 本论文研究为激光工程中激光小尺度畸变波前探测精度提高提供了有益的探索与可行性方法。更多还原

【Abstract】 The control of laser beam quality is one of important basis which ensure the circulating security of the laser system and enhancing power effectively in the field of high power laser system, in which the diagnosis and control of small-scale distorted wavefront is a key issue. In this paper, the laser small-scale distorted wavefront sensing accuracy and measurement error are theoretically analyzed and experimentally researched, using the Fresnel zone plate arrays as wavefront sensor. The main research contents and innovative results can be summarized as follows:1. According to the principle of Hartmann- Shack wavefront sensor (HS WS), we put forward the Fresnel zone plate arrays as wavefront sensor. Also, We discuss the sensitivity and dynamic range of the HSWS and analyze the focus characteristic of the Fresnel zone plate array by experiment.2. We analyze the influence of the random noise of light source and the structure of Fresnel zone plate arrays on the wavefront reconstruction, and this study will offer reference in optimizing design of the system and practical operation in the measurement and control of small-scale distorted wavefront.3. According to analyzing the five kinds of inhibiting noise methods, the two nonlinear filtering algorithms are showed to be the optimal selection. Also, we apply Bi-cubic interpretation to light spot image in order to improve accuracy of centriod algorithm.4. We propose another new centriod algorithm based on optimizing detecting window in order to improve the centroid detecting precision and raise the wavefrontreconstruction accuracy.5. We build an adaptive optical system for the measurement of distorted wavefront of the long-focus lens and plane crystal glasses. The elementary experimental results prove the validity and stability of the new centroid algorithms based on optimizing detecting window and Bi-cubic interpretation presented in the paper.Our research results provide valuable reference to the real project in enhancement of the detecting accuracy in the laser small-scale distorted wavefront measurement.更多还原