Far-field imaging of acoustic waves by a two-dimensional sonic crystal

The negative refraction behavior and imaging effect for acoustic waves in two-dimensional sonic crystals consisting of hexagonal arrays of steel cylinders in air are studied in this paper. The negative refraction and left-handed behaviors are demonstrated by the simulation of a Gaussian beam through a slab of the sonic crystal. Imaging effects by the sonic crystal slab with effective refraction index n not equal -1 and n=-1 are investigated, respectively. Far-field images by two-dimensional sonic-crystal-based superlens for both cases are obtained by exact numerical simulations, which is in agreement with the physical analysis based on the wave-beam negative refraction law. Thus, extensive applications of such a phenomenon to acoustic devices are anticipated.