Low Temperature Physics: 42, 354 (2016); https://doi.org/10.1063/1.4948617
Rayleigh and Wood anomalies in the diffraction of acoustic waves from the periodically corrugated surface of an elastic medium
Department of Physics and Astronomy, University of California, Irvine CA 92697, U.S.A.
Department of Physics, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
Received November 20, 2015
By the use of the Rayleigh method we have calculated the angular dependence of the reflectivity and the efficiencies of several other diffracted orders when the periodically corrugated surface of an isotropic elastic medium is illuminated by a volume acoustic wave of shear horizontal polarization. These dependencies display the signatures of Rayleigh and Wood anomalies, usually associated with the diffraction of light from a metallic grating. The Rayleigh anomalies occur at angles of incidence at which a diffracted order appears or disappears; the Wood anomalies here are caused by the excitation of the shear horizontal surface acoustic waves supported by the periodically corrugated surface of an isotropic elastic medium. The dispersion curves of these waves in both the nonradiative and radiative regions of the frequency-wavenumber plane are calculated, and used in predicting the angles of incidence at which the Wood anomalies are expected to occur.
PACS: 62.30.+d Mechanical and elastic waves; vibrations;
Key words: elastic medium, surface waves, Rayleigh and Wood anomalies.
Published online: March 23, 2016