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.

Laser-ultrasound-based non-destructive testing—optimization of the thermoelastic source

“…The experimental set-up basis used to generate and detect the surface acoustic waves is represented in figure 1 [9]. A 10 ns duration Q-switched Nd:YAG laser pulse of 532 nm wavelength is shaped following different set-ups.…”

Experimental and numerical study of Conoscopic Interferometry sensitivity for optimal acoustic pulse detection in ultrafast acoustics

“…Photoacoustics uses pulsed lasers to excite high-frequency acoustic waves ranging from hundreds of kHz to hundreds of GHz [1,2] for nondestructive testing [3], material characterization [4], and for medical imaging and diagnosis [5]. Usually, a nanosecond (ns) [6] to femtosecond (fs) [7] pulsed laser -the pump -generates bulk, guided, or surface acoustic waves in a sample of interest [8]. The detection of the same acoustic waves with a second laser beam -the probe -enables noncontact measurements on samples with complex geometries, in tough environmental conditions, and without contaminating their surface [3].…”

Conoscopic interferometry for optimal acoustic pulse detection in ultrafast acoustics

“…Photoacoustics uses pulsed lasers to excite highfrequency acoustic waves ranging from hundreds of kHz to hundreds of GHz [1] [2] for non-destructive testing [3], material characterization [4], and for medical imaging and diagnosis [5]. Usually, a nanosecond (ns) [6] to femtosecond (fs) [7] pulsed laser -the pump -generates bulk, guided, or surface acoustic waves in a sample of interest [8]. The detection of the same acoustic waves with a second laser beam -the probe -enables non-contact measurements on samples with complex geometries, in tough environmental conditions, and without contaminating their surface [3].…”