Negative refraction of acoustic waves using a foam-like metallic structure

A phononic crystal (PC) slab made of a single metallic phase is shown, theoretically and experimentally, to display perfect negative index matching and focusing capability when surrounded with water. The proposed PC slab is a centimeter scale hollow metallic foam-like structure in which acoustic energy is mediated via the metal lattice. The negative index property arises from an isolated branch of the dispersion curves corresponding to a mode that can be coupled to incident acoustic waves in surrounding water. This band also intercepts the water sound line at a frequency in the ultrasonic range. The metallic structure is consequently a candidate for the negative refraction of incident longitudinal waves.

[1]  F. J. García de abajo,et al.  Anisotropic metamaterials for full control of acoustic waves. , 2012, Physical review letters.

[2]  Zhengyou Liu,et al.  Negative refraction of acoustic waves in two-dimensional phononic crystals , 2004 .

[3]  Chen-Yu Chiang,et al.  Imaging off-plane shear waves with a two-dimensional phononic crystal lens , 2010, Journal of physics. Condensed matter : an Institute of Physics journal.

[4]  J. Zi,et al.  Negative birefraction of acoustic waves in a sonic crystal. , 2007, Nature materials.

[5]  Bruno Morvan,et al.  Experimental demonstration of the negative refraction of a transverse elastic wave in a two-dimensional solid phononic crystal , 2010 .

[6]  Yan Pennec,et al.  Two-dimensional phononic crystals: Examples and applications , 2010 .

[7]  Anne-Christine Hladky-Hennion,et al.  Analysis of the propagation of plane acoustic waves in passive periodic materials using the finite element method , 1995 .

[8]  P. Sheng,et al.  Negative-refraction imaging with two-dimensional phononic crystals , 2005 .

[9]  J. Zi,et al.  Negative refraction of acoustic waves in two-dimensional sonic crystals , 2005 .

[10]  John H. Page,et al.  Negative refraction and focusing of ultrasound in two-dimensional phononic crystals , 2008 .

[11]  Anqi Zhang,et al.  Acoustic far-field focusing effect for two-dimensional graded negative refractive-index sonic crystals , 2010 .

[12]  John H. Page,et al.  Resolution limit of a phononic crystal superlens , 2011 .

[13]  Bruno Morvan,et al.  Negative refraction of longitudinal waves in a two-dimensional solid-solid phononic crystal , 2011 .

[14]  Yan-Bin Chen,et al.  Acoustic backward-wave negative refractions in the second band of a sonic crystal. , 2006, Physical review letters.

[15]  A. Norris.  Acoustic cloaking theory , 2008, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[16]  M. Kushwaha,et al.  CLASSICAL BAND STRUCTURE OF PERIODIC ELASTIC COMPOSITES , 1996 .