Laser Ultrasonic Imaging of Flat-Bottom-Drilled Holes

Laser ultrasonics is an emerging ultrasonic nondestructive evaluation technology that has attractive properties of being noncontact [1] and possessing broad frequency components, especially in the higher frequency end [1,2]. When laser beams are used to generate and detect ultrasound, the laser beams are often focused to small spots on a specimen’s surface. A laser ultrasonic system can often be modeled as a point-source-point-receiver system, which makes ray tracing analysis simpler [3]