Estimation via Laser Ultrasonics of the Ultrasonic Attenuation in a Polycrystalline Aluminum Thin Plate Using Complex Wavenumber Recovery in the Vicinity of a Zero-Group-Velocity Lamb Mode

In this paper, we present a method to recover the complex wavenumber dispersion relations using spatial Laplace transform from experimental spatiotemporal signals measured by laser ultrasonic technique. The proposed was applied on zero-group-velocity Lamb modes in order extract attenuation polycrystalline aluminum plate of about 70 ?m thickness. difference between and theoretical Fourier transforms minimized least square sense amplitudes wavenumbers at 40 MHz. results were compared values reported literature that other means those estimated quality factor extracted single temporal signal.