【作者】 赵军普；

【导师】 彭翰生；

【作者基本信息】 四川大学 ， 光学， 2006， 硕士

【摘要】 光束质量诊断是激光领域的一项重要基础研究内容，从激光出现到目前一直备受关注，但是由于不同应用目的对光束“质”的要求不同，因此光束质量评价至今没有形成统一的标准，也未建立起标准的测量方法。惯性约束聚变(ICF)领域的激光驱动装置，运行于高功率密度状态，因而非线性效应明显，元件破坏风险大；系统庞大影响因素复杂，对测量精度要求却很高，加之对光束近远场强度分布要求特殊，因此对描述光束质量的评价参数必须进行有针对性的研究，光束质量测量也必须寻找各种非相关的手段以验证测量结果的可靠性和准确性。本文在目前ICF固体激光驱动装置光束质量评价和测量方法的基础上，围绕光束质量诊断中两个急待解决的问题：光束近场调制评价和光束质量诊断系统自身验证问题开展了研究工作，主要内容包括以下几个方面： 1．基于数理统计理论，建立了通量概率密度和功率谱密度两种近场光束质量评价模型，研究了两者之间的联系，提出中频对比度、特征频率和σ调制度作为新的近场评价参数。 2．根据两种近场评价模型，对TIL装置从静态到5.0GW／cm~2高强度输出光束近场强度分布进行了统计分析。研究表明，空间频域分析方法更具优越性，并依据特征频率找出了近场的小尺度固定周期性调制来源，结合模拟计算结果验证了实验分析的正确性。且在此基础上，研究了周期调制光束离开系统后在自由空间传输的演化特性。 3．利用空间位相调制的径向剪切干涉仪，研究了从单幅干涉图中获取高功率激光装置光束波前位相、近场和远场，从而实现光束质量综合诊断的方法。通过50J能量之内的干涉仪测量结果和CCD直接测量结果之间的对比，验证了更多还原

【Abstract】 Beam quality diagnosis is one of the important foundation contents in Laser research field. The requirement is different for different application purpose, so there is not a standard to evaluate beam quality and a method to measure beam parameter up to now. In the Inertial Confinement Fusion (ICF) filed, the laser facility works in the high intensity state, so nonlinear effects are obvious and damage risk of optical element is serious. The precise measurement is required for the large system with complicated influence factors, so the beam quality characterization must be researched specially and the measurement must find some non-related methods to verify the accuracy at the same time. This thesis focuses on two urgent problems: near field beam quality characterization and self certification of beam quality diagnostic system. The main results obtained here can be summarized as follows:1. Based on the mathematical statistics, two characterization models for near field beam quality have been built up: fluence distribution and power spectral density. Relationship between the two models is studied, and then a modulation, median frequency contrast RMS_v and characteristic frequency V_T were extracted as new near field evaluation parameter.2. Output near field of TIL from static state to 5GW/cm~were analyzed by the two near filed evaluation models. It is found that the spatial frequency method is more advantageous than the spatial domain method. The source of stable near field periodic modulation was found by characteristic frequency of it, then the reliability更多还原