마이켈슨 간섭계를 이용한 레이저 여기 초음파의 검출

초록

A stabilized Michelson Interferometer is proposed in order to detect the laser-generated ultrasonic waves in free from the external noise such as low frequency mechanical vibration. In order to confirm the performance, theoretically expected waveforms were compared with experimentally detected ones in thermo-elestic region, where we generated ultrasonic wave in steel disk by using a Q-switched Nd:YAG laser. Also sound velocities of longitudinal and shear components were measured and they showed good agreement with the typical values in steel. Finally, the change of sound velocity according to the temporature change was measured to show that the proposed technique could be applied to the characterization of high temperature materials.