Fast slot characterization using laser ultrasonics and mode conversion

Abstract

A fast slot detection and characterization method using all-optical ultrasound generation and detection is presented in this paper. It is based on the relative properties of the Rayleigh wave transmitted by a slot and the Rayleigh wave mode-converted from the head wave. Considering finite element analysis, it appears that only one A-scan is necessary to both detect the slot position and evaluate its depth. Good agreement has been found with experiments carried out on an aluminium sample with a laser line source and an interferometric optical probe.