激光参数对激光激发超声信号的影响分析

研究了激光参数对激光激发超声信号的影响.研究中首先理论分析激光激发超声过程中,激光参数对激发超声信号的影响.同时,设计并搭建一种激光激发超声的实验装置,实验验证理论分析结果.该实验装置应用脉冲激光配合光衰减结构对被测目标激发产生超声波,通过超声探头实现激光超声信号的探测.实验中以铝板为检测对象,对激光脉冲能量和照射光斑大小对激发超声信号的影响进行实验分析.通过理论分析及实验验证,可得出照射光斑直径与激光能量会直接影响入射激光功率密度,从而影响激发超声的幅度.

Analysis of the influence of laser parameters on laser ultrasonic signals

The influence of laser parameters on laser ultrasonic signals is studied. Firstly, the physical mechanisms of ultrasonic generation by laser pulse and the influence of laser parameters on the ultrasonic signal are analyzed theoretically. And an experimental apparatus is designed and built to verify the theoretical analysis results. In the experiment the ultrasonic is generated with pulse laser and optical attenuation unit, and then the detection of laser ultrasonic signals is achieved by a piezoelectric ultrasonic transducer. In the experiment, the influence of the pulse laser energy and laser spot diameter on ultrasonic signal is studied with an aluminum plate. Through theoretical analysis and experimental verification, the laser power density can be affected by the laser spot diameter and laser energy, which will affect the generated ultrasonic amplitude.