Theory and applications of laser generated zero-group velocity lamb mode resonance

T. W. Murray, O. Balogun, C. Prada, D. Clorennec, D. Royer

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Lamb modes exhibit a resonant behavior at frequencies where the group velocity vanishes while the phase velocity remains finite. This type of zero group velocity (ZGV) point exists in most isotropic materials at the minimum frequency-thickness product of the first order symmetric (S1) Lamb mode. Laser sources couple efficiently into this resonance and a sharp peak is observed with source and receiver on epicentre. A model for the laser generation of ultrasound in thin plates using an amplitude modulated laser source is presented. Lamb wave displacement spectra are measured using an amplitude modulated laser source for excitation and a Michelson interferometer coupled to an RF lock-in amplifier for detection. The displacement spectra of Lamb waves generated in micron scale plates show good agreement with theoretical predictions. Experimental results are presented demonstrating excitation of the S1 ZGV resonance in a 4μm thick membrane using a high frequency (700MHz) amplitude modulated laser source. Subsurface features below the membrane are detected by tracking the S1 ZGV resonance peak as the sample is scanned.

Original languageEnglish (US)
Title of host publicationReview of Progress in QuantitativeNondestructive Evaluation
Pages255-262
Number of pages8
DOIs
StatePublished - Mar 24 2008
Event34th Annual Review of Progress in Quantitative Nondestructive Evaluation - Golden, CO, United States
Duration: Jul 22 2007Jul 27 2007

Publication series

NameAIP Conference Proceedings
Volume975
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

Other34th Annual Review of Progress in Quantitative Nondestructive Evaluation
CountryUnited States
CityGolden, CO
Period7/22/077/27/07

    Fingerprint

Keywords

  • Lamb waves
  • Laser ultrasonics
  • Plates

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Murray, T. W., Balogun, O., Prada, C., Clorennec, D., & Royer, D. (2008). Theory and applications of laser generated zero-group velocity lamb mode resonance. In Review of Progress in QuantitativeNondestructive Evaluation (pp. 255-262). (AIP Conference Proceedings; Vol. 975). https://doi.org/10.1063/1.2902667