利用激光超声技术测量介观尺度材料的声速

摘要

设计并建立了一种可用于测量介观尺度(几十微米至几毫米)材料声速的激光超声系统.该系统采用脉宽为6.3 ns的调Q激光器作为超声波激发光源,使用光纤位移干涉仪进行超声位移探测.利用新建立的激光超声系统,测量了不同厚度铜箔的纵波声速.结果表明,激光超声系统得到的声速具有较高精度,可以将其应用于介观尺度材料声速测量.%A laser-based ultrasound system was designed and built to measure the sound velocity of mesoscale (tens of micrometer- to millimeter-sized) objects. The system uses a Q-switch laser with 6.3 ns pulse width for excitation of broadband ultrasonic waves,and an optical fiber displacement interferometer for detection. The longitudinal acoustic wave velocities of the copper foils with different thicknesses were presented, which exhibit a relatively high degree of accuracy.