Self collimation of ultrasound in a 3D sonic crystal

TL;DR

This paper experimentally demonstrates that a 3D sonic crystal can self-collimate ultrasonic beams, maintaining a narrow beam profile during propagation, which could enhance ultrasonic applications.

Contribution

The study provides the first experimental evidence of 3D self-collimation of ultrasound in a sonic crystal with a novel crossed steel cylinder structure.

Findings

Ultrasonic beam remains narrow inside the crystal

Self-collimation occurs in a 3D sonic crystal

Beam spreading is suppressed by the crystal structure

Abstract

We present the experimental demonstration of self-collimation (subdiffractive propagation) of an ultrasonic beam inside a three-dimensional sonic crystal. The crystal is formed by two crossed steel cylinders structures in a woodpile-like geometry disposed in water. Measurements of the 3D field distribution show that a narrow beam which diffractively spreads in the absence of the sonic crystal is strongly collimated in propagation inside the crystal, demonstrating the 3D self-collimation effect.