Spatially resolved acoustic spectroscopy for fast noncontact imaging of material microstructure

We have developed a noncontact and nondestructive technique that uses laser-generated and detected surface acoustic waves to rapidly determine the local acoustic velocity, in order to map the microstructure of multi-grained materials. Optical fringes excite surface waves at a fixed frequency, and th...

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Veröffentlicht in:Optics express 2006-10, Vol.14 (22), p.10435-10440
Hauptverfasser: Sharples, Steve D, Clark, Matthew, Somekh, Mike G
Format: Artikel
Sprache:eng
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Zusammenfassung:We have developed a noncontact and nondestructive technique that uses laser-generated and detected surface acoustic waves to rapidly determine the local acoustic velocity, in order to map the microstructure of multi-grained materials. Optical fringes excite surface waves at a fixed frequency, and the generation efficiency is determined by how closely the fringe spacing matches the acoustic wavelength in the excitation region. Images of titanium alloys are presented, acquired using the technique. Methods to improve the current lateral resolution of 0.8mm are discussed, and the ability to measure velocity change to an accuracy of one part in 3300 is experimentally demonstrated.
ISSN:1094-4087
1094-4087
DOI:10.1364/oe.14.010435