基于光外差干涉检测激光超射波技术研究.doc

清华 大学 2012 届毕业设计说明书I 目录目录1 引言..............................................................................................................................11.1 课题背景...................................................................................................................11.2 国内外发展状况.......................................................................................................11.3 课题意义...................................................................................................................31.4 课题内容...................................................................................................................32 激光超声激励技术研究..............................................................................................52.1 超声波的性质...........................................................................................................52.1.1 超声波的分类..........................................................................................................52.1.2 超声波的特点........................................................................................................52.1.3 超声波的波型与声速............................................................................................62.1.4 超声波的反射折射及波型转换............................................................................62.2 超声波的检测...........................................................................................................72.3 激光产生超声的原理...............................................................................................92.4 Nd:YAG 激光器激励超声波..................................................................................102.4.1 Nd:YAG 激光介绍...............................................................................................102.4.2 Nd:YAG 激光器工作原理...................................................................................102.5 本章小结.................................................................................................................113 激光外差干涉概述......................................................................................................133.1 光电检测.................................................................................................................133.1.1 系统分类................................................................................................................133.1.2 激光超声检测......................................................................................................163.2 光外差干涉测试技术.............................................................................................173.2.1 概述......................................................................................................................173.2.2 光外差干涉原理..................................................................................................173.2.3 光外差探测系统..................................................................................................183.3 激光外差干涉测试系统.........................................................................................193.3.1 测试系统的原理..................................................................................................193.3.2 激光外差干涉测长..............................................................................................21清华 大学 2012 届毕业设计说明书II 3.4 光外差检测优势.....................................................................................................233.5 本章小结...................................................................................................................244 光外差干涉法检测激光超声的设计和实现..............................................................254.1 声光调制.................................................................................................................254.1.1 声光调制器原理 .................................................................................................254.1.2 声光调制分类......................................................................................................274.2 系统设计.................................................................................................................284.2.1 外差干涉系统构成..............................................................................................294.2.1 超声信号检测原理..............................................................................................304.2.2 光外差干涉法检测激光超声原理......................................................................314.3 光路调试结果.........................................................................................................324.4 本章小结.................................................................................................................335 总结............................................................................................................................345.1 主要工作.................................................................................................................345.2 系统存在问题.................................................................................。