激光超声是近些年来发展较快的研究课题。它应用于无损检测的一个重要问题如何测量微振动。由于需检测的对象是小于10~(-10)m数量级的微振动,一般采用干涉仪作为检测的主要手段。干涉仪可以测量微振动,主要有麦克尔逊干涉仪、法布里-珀罗干涉仪等。用干涉仪测量微小振动面临的主要困难是提高测量精度和整个系统的稳定性,使整个系统具有较好的抗干扰性能。我们在研究中采用了激光频率锁定方法。其 Laser ultrasound is a rapidly growing research topic in recent years. It is an important issue that should be applied to nondestructive testing how to measure micro vibration. As the object to be detected is less than the magnitude of 10 ~ (-10) m micro-vibration, the interferometer is generally used as the main means of detection. Interferometer can measure micro vibration, mainly Michelson interferometer, Fabry-Perot interferometer and so on. The main difficulty of measuring the tiny vibration with the interferometer is to improve the measurement accuracy and the stability of the whole system, so that the whole system has better anti-interference performance. We used a laser frequency locking method in the study. its