Article

Sonic gradient index lens for aqueous applications

Acoustics Division, Naval Research Laboratory, Washington, DC 20375, USA
Applied Physics Letters (Impact Factor: 3.79). 10/2010; DOI: 10.1063/1.3489373
Source: IEEE Xplore

ABSTRACT We study the acoustic scattering properties of a phononic crystal designed to behave as a gradient index lens in water, both experimentally and theoretically. The gradient index lens is designed using a square lattice of stainless-steel cylinders based on a multiple scattering approach in the homogenization limit. We experimentally demonstrate that the lens follows the graded index equations derived for optics by mapping the pressure intensity generated from a spherical source at 20 kHz. We find good agreement between the experimental result and theoretical modeling based on multiple scattering theory.

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    ABSTRACT: We design and characterize a sonic crystal (SC) to manipulate the propag waves by numerical simulation based on the time-domain (FDTD) method and by ultrason Two types of SC for an acoustic lens effect are homogeneous periodic structure exhibiting ne and the other has a hetero-structure. Ne behavior in the simulation is good agreement wi in the frequency range around 1.2MHz. We al effect for far-field wave in the hetero-structu results indicate that a novel energy-transm device can be designed using SCs. Index Terms — sonic crystal, acoustic lens, ne FDTD simulation, ultrasonic measurement, ener
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