Beam paths of flexural Lamb waves at high frequency in the first band within phononic crystal-based acoustic lenses

Abstract

International audienceThis work deals with an analytical and numerical study of the focusing of the lowest order anti-symmetric Lamb wave in gradient index phononic crystals. Computing the ray trajectories of the elastic beam allowed us to analyze the lateral dimensions and shape of the focus, either in the inner or behind the phononic crystal-based acoustic lenses, for frequencies within a broad range in the first band. We analyzed and discussed the focus-ing behaviors inside the acoustic lenses where the focalization at sub-wavelength scale was achieved. The focalization behind the gradient index phononic crystal is shown to be efficient as well: we report on FMHM = 0.63λ at 11MHz

Preface to Special Topic: Selected Articles from Phononics 2013: The Second International Conference on Phononic Crystals/Metamaterials, Phonon Transport and Optomechanics, 2-7 June 2013, Sharm El-Sheikh, Egypt

“…14 Other contributions to macroscale applications include analysis of the shape, size and location of the focus area generated by gradient-index acoustic lenses based on phononic crystals 15 and analysis of the dispersion characteristics of beam-like planar lattice structures exhibiting out-of-plane motion. 16 The interaction of elastic waves with optical waves, i.e., optomechanics, is another topic discussed in the article collection.…”