Laser ultrasonic inspection in ablation regime

This article presents a laser-based ultrasonic technique (LBUT) in ablation regime for inspection of internal defects using the pulsed high-power laser (HPL) and two wave mixing (TWM) detector. Pulsed HPL source has been recognized as a good ultrasonic generator to overcome weakness of the conventional contact transducer in harsh environment such as high temperature and rough surface of measurement target. And TWM detecting as non-contact method was used to measure the displacement by laser ultrasonic wave. The aim of this study is to investigate transmission characteristics of laser ultrasonic to various internal defects by the fully non-contact LBUT. Experimental results for various artificial internal defects showed the usefulness of the LBUT in ablation regime in nondestructive testing (NDT) field.