In this paper we present a complete non-contact, all-optical inspection tool, for the extraction of the principal mechanical
characteristics of plate-like structural materials (effective stiffness, Poisson ratio and plate's thickness).
Broadband ultrasonic guided waves - Lamb waves - are optically generated and detected for incremental source detector
distances. A two dimensional Fourier transform is applied to these measured time signals in order to extract dispersion
information, which is highly affected by elastic properties as well as by sample geometry.
The elastic properties and thickness of the structure under test are obtained from this experimentally extracted dispersion
information, by an inversion technique which is presented and analysed in the paper. These values are verified with a
Monitoring changes in the estimated material properties could be used to indicate changes in the structural condition.
This paper describes an all optical non-contact technique to determine material properties in a mechanical structure. Using optical generation of ultrasound and interferometric optical detection to determine the dispersion curves for acoustic (Lamb) waves, readily available numerical algorithms have produced values of Young's Modulus and Poisson ratio with confidence limits of a few percent. The approach may be applied to inspection regions with dimension in the range microns to centimetres.