DAC加载下材料高压声速的激光超声测量技术

High Pressure Sound Velocity Measurement of Material in DAC Using Laser Ultrasonics Technique

设计并建立了可测量金刚石压砧(DAC)加载下材料高压声速的激光超声系统。该系统采用脉宽为6.3ns的调Q激光器作为超声波激发光源,使用光纤位移干涉仪和速度干涉仪混合系统进行超声位移探测,不需要借助其它任何参数即可直接测量样品的高压声速和原位厚度。利用该系统,测量了2.6GPa压力下铜样品的高压纵波声速和原位厚度,并给出了测量结果。

A prototype laser-based ultrasound system is designed and built to measure the sound velocity of samples at high pressure in a diamond anvil cell.The system uses a Q-switch laser with 6.3 ns pulse width for excitation of broadband ultrasonic waves,and an optical fiber displacement and velocity mixing interferometer for detection.Both longitudinal acoustic wave velocity and in-situ thickness of copper at the pressure of 2.6 GPa are obtained by this all-optical pump-probe technique,which does not require any information beyond that contained in the signal itself.