Experimental study of guiding and filtering of acoustic waves in a two dimensional ultrasonic crystal

Abdelkrim Khelif (1) , Abdelkrim Choujaa (1) , Sarah Benchabane (1) , Bahram Djafari-Rouhani (2) , Vincent Laude (1)

1 FEMTO-ST - Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174)
2 LDSMM - Laboratoire de dynamique et structure des matériaux moléculaires

We present a combined experimental and theoretical study of the guiding, bending and filtering of acoustic waves in an ultrasonic crystal. The crystal consists of a two-dimensional periodical array of steel rods immersed in water, for wich a complete acoustic band gap extending from 240 to 325 kHz is found experimentally. Waveguides for acoustic waves are further created by removing a line defect, on which stubs can be added by removing rods from the side-walls of the waveguide. Full transmission is observed for a one-period-wide straight waveguide within the full-band-gap of the perfect phononic crystal, i.e. for a waveguide aperture smaller than one acoustic wavelength. Waveguiding over a wide frequency range is also obtained for a one-period-wide waveguide with two sharp 90 bends. Finite-difference time-domain computations are found to be in good agreement with the measurements in all experimental configurations.

Domaines: Acoustique [physics.class-ph]; Acoustique [physics.class-ph]

Abdelkrim Khelif, Abdelkrim Choujaa, Sarah Benchabane, Bahram Djafari-Rouhani, Vincent Laude. Experimental study of guiding and filtering of acoustic waves in a two dimensional ultrasonic crystal. Zeitschrift für Kristallographie, 2005, 220, pp.836. ⟨hal-00074880⟩