Analysis of Metallic Multilayers Using Hypersonic Surface Waves Induced by Transient Reflecting Gratings

Abstract
Gigahertz surface acoustic waves (the Rayleigh-like modes) have been optically generated and detected on ultrathin (<1 µm) metallic single-layer and multilayered films attached to glass substrates using the laser-induced transient reflecting grating (TRG) technique. The dispersion relations of the excited Rayleigh-like modes could be constructed experimentally and theoretically. By finding the best fitting of the theoretical dispersion curves to the experimental data, this method can be used to deduce the elastic constants of ultrathin multilayered films.