Sonic Gradient Index Lens for Aqueous Applications

TL;DR

This paper presents the design and experimental validation of a sonic gradient index lens in water using a phononic crystal, demonstrating its ability to focus sound waves with good agreement between theory and experiment.

Contribution

It introduces a novel gradient index lens for acoustic applications in water based on a square lattice of stainless-steel cylinders, validated through experiments and multiple scattering theory.

Findings

The lens accurately follows graded index equations derived from optics.

Experimental results align well with theoretical predictions.

The design enables effective acoustic focusing in aqueous environments.

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.