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Proceedings Paper

Surface-generated ultrasonic waves in solids by a Nd-YAG laser
Author(s): David C. Emmony; Barry Ward
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Paper Abstract

A Q switched Nd-YAG laser has been used to generate ultrasonic waves at air-solid boundaries. The high energy and power density at the laser focus leads to the formation of a plasma on the surface of the solid. The solid surface is heated to the vaporization point and the combined effects of the laser plasma and surface ablation lead to shock waves in the air and a high pressure transient acoustic wave in the solid. This laser generated ultrasound is being used to study material properties and is used in non-destructive testing. Laser ultrasound has been studied using a range of transducers to confirm the thermoelastic and ablation regimes. But in general these techniques do not give the spatial as well as temporal behavior of the waves. Schlieren photography using a dye laser has been used to study the propagation of the various wave types at an air-solid boundary and Mach Zehnder interferometry has been used to determine the absolute pressure in transparent solids. The pressure has been measured as a function of time and the radial dependence is in excellent agreement with the direct pressure transducer measurements of other workers in the ablation regime.

Paper Details

Date Published: 1 January 1993
PDF: 8 pages
Proc. SPIE 1801, 20th International Congress on High Speed Photography and Photonics, (1 January 1993); doi: 10.1117/12.145724
Show Author Affiliations
David C. Emmony, Loughborough Univ. of Technology (United Kingdom)
Barry Ward, Loughborough Univ. of Technology (United Kingdom)

Published in SPIE Proceedings Vol. 1801:
20th International Congress on High Speed Photography and Photonics
John Marks Dewey; Roberto G. Racca, Editor(s)

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