Abstract : a laser damage facilities , which has mm size spot and operates in tem00 mode ， were achieved . in order to know the reasons of laser damage , the laser energy density was controlled near the damage threshold of the oxide thin films . according to the examined near - threshold damage morphology , the damage mechanisms of the optical coatings can be divided into two types . one was caused by melting of the coating materials , another by exploding , induced with the inner stress of the film . the plasma generated was an important reason to expand the damage area 文摘:采用毫米量级大光斑的近单模的激光器，控制入射薄膜表面的激光能量，获得了几种常见单层膜和增透膜的损伤形貌，实验结果表明，薄膜的损伤可区分为熔化型和应力型两种，薄膜表面等离子体对损伤斑点的扩大有重要作用。
In this paper we designed the relief height of the computer optical elements mainly based on the geometrical theory and the scalar quantity diffractive theory . based on the geometrical theory , we achieved the height of phase relief that can shape the laser beam into 4 square spots , square frame , 1 square spot ; with the computer simulation and drawing program , the diffraction patterns are gotten in this paper , the results agreed with the anticipated diffraction patterns ; in this paper we also discussed the affects to the diffraction patterns by changing some parameters 本文主要基于几何理论和标量理论来设计计算机光学元件表面的浮雕高度,文中用几何理论推导出了把高斯光束整形为四个矩形光斑束,正方框形光束、矩形平顶光斑的计算机光学元件表面的浮雕公式;通过计算机辅助设计,计算得到了计算机光学元件表面上的浮雕高度,设计出了计算机光学元件。
Abstract : the far - field spot characteristics of laser converted by random phase plate are analyzed theoretically , including the shape , size , rotational symmetry and diffractive efficiency of the spots , as well as the distribution of subsidiary spot . by comparing the influence of phase element shape ( triangular , square and hexagonal ) on the characteristics , we found that the random phase plate with hexagonal array structure is more suitable for the beam smoothing in laser fusion 文摘:从理论上分析了激光经随机位相板变换后在远场的光斑特性(包括光斑的形状、大小、旋转对称性、衍射效率以及旁瓣分布) ，通过比较三种形状位相元(等边三角形、正方形和正六边形)的远场光斑特性，得知正六边形位相元结构的随机位相板更适合于激光聚变中的束匀化。
Because the element of the far field diagnosis system which is used to detecte facula is ccd , when it works , much types of noise will affect it , and threshold value will affect the efficient signal . in this paper , hartmann - shack wavefront sensor which can detect the phase of beam is studied , what is detected by hartmann - shack wavefront sensor can be transform into far field , and we compare this result with that detected by the far field diagnosis system , and we can know which system is more accurate 事实上， hartmann - shack波前传感器的ccd在探测光斑阵列时，也同样受ccd噪声因素的影响，并且还有波前本身的复原误差，但是hartamnn - shack波前传感器的ccd噪声影响的是波前复原精度，虽然这也将导致事后处理远场光斑的误差，但这种误差与远场测量系统的误差相比孰大孰小是本文研究的主要内容。
First , we can use a camera to take over the laser beam at one end , record the position of the light - spot , and calculate the centroid of the light - spot , then , move the laser on the guide rail . we should rectify the screw until the position of light - spot is unchangeable . then , the camera should be moved to the other end of the guide rail 先用摄像机在一端接收激光器发出的光斑,并记录光斑的位置,求出其质心,然后在导轨上移动激光器,调节顶丝,直到摄像机上的光斑位置不动为止,然后将激光器移到导轨另一端,让激光器在导轨上滑动,调节顶丝,直到摄像机上光斑位置不变,而且与前一次测试时的位置在误差允许的范围内,则认为激光器直线性校准完毕。
