Experimental evidence of isotropic transparency and complete band gap formation for ultrasounds propagating in stealth hyperuniform media

TL;DR

This study experimentally demonstrates that ultrasounds in stealth hyperuniform media exhibit isotropic transparency and complete band gaps, highlighting their potential for designing advanced functional materials.

Contribution

First experimental evidence of isotropic transparency and complete band gaps for ultrasounds in 2D stealth hyperuniform media, advancing understanding of wave transport in correlated structures.

Findings

Transparency cancels effective attenuation of ultrasound.

A band gap occurs near the first Bragg frequency.

Isotropy of transparency and band gap confirmed in various geometries.

Abstract

Following on recent experimental characterization of the transport properties of stealth hyperuniform media for electromagnetic and acoustic waves, we report here measurements at ultrasonic frequencies of the multiple scattering of waves by 2D hyperuniform distributions of steel rods immersed in water. The transparency, for which the effective attenuation of the medium is cancelled, is first evidenced by measuring the transmission of a plane wave propagating in a highly correlated and relatively dense medium. It is shown that a band gap occurs in the vicinity of the first Bragg frequency. The isotropy of both transparency and bang gap are also evidenced for the case of waves generated by a point source in differently ordered and circular shaped distributions. In other words, we thus obtain a representation of the Green's function. Our results demonstrate the huge potential of hyperuniform as well as highly correlated media for the design of functional materials.