Title :
Experimental study of band gaps and defect modes in a two-dimensional ultrasonic crystal
Author :
Khelif, A. ; Choujaa, A. ; Laihem, R. ; Wilm, M. ; Ballandras, S. ; Laude, V. ; Solal, M.
Author_Institution :
Lab. de Phys. et de Metrol. des Oscillateurs, Associe a l´´Univ. de Franche-Comte, Besancon, France
Abstract :
We report on the experimental observation of the existence and the interaction of localized defect modes in a full acoustic band gap in a two-dimensional lattice of steel cylinders immersed in water. The confinement of defect modes and the splitting of their resonance frequencies are observed and are explained by their evanescent coupling. A new type of waveguiding in a phononic crystal based on the evanescent coupling of defect modes is proposed and demonstrated experimentally. The finite-difference time-domain (FDTD) method is used to interpret the experimental data and it is found that theoretical predictions properly account for the observed spectra.
Keywords :
acoustic waveguides; crystal defects; energy gap; finite difference time-domain analysis; localised modes; localised states; steel; FDTD; acoustic band gaps; finite difference time-domain method; localized defect modes; phononic crystal; resonance frequency; steel cylinders; two-dimensional lattice; two-dimensional ultrasonic crystal; Finite difference methods; Lattices; Photonic band gap; Photonic crystals; Resonance; Resonant frequency; Solids; Steel; Time domain analysis; Transmission line matrix methods;
Conference_Titel :
Ultrasonics, 2003 IEEE Symposium on
Print_ISBN :
0-7803-7922-5
DOI :
10.1109/ULTSYM.2003.1293426
