Propagation of elastic waves in structured media
Author : Etienne Coffy
all affiliated at : Institut FEMTO-ST, CNRS, ENSMM, Univ. Bourgogne Franche-Comté
Abstract : The presentation will be about the propagation of elastic waves in structured media and will be divided in two parts. The first part will adress one-dimensional phononic crystals, also called phononic crystal strips. Based on a fine study of the modes and the underlying physics, an optimization of the band gap of a phononic structure consisting of pillars on a thin strip will be discussed. Experimental results, validating the numerical study will also be shown. The second part will concern the study of the wave propagation in columnar tungsten thin films deposited by the GLancing Angle Deposition (GLAD) method. Characterized with a femtosecond heterodyne pump-probe setup (ASynchroneous OPtical Sampling (ASOPS) technique), the propagation of the surface acoustic waves is demonstrated to be anisotropic for GLAD samples deposited with high angles. A numerical model, developped to explain the anisotropy mechanisms, will be presented.