Transverse confinement of ultrasound through the Anderson transition in 3D mesoglasses

TL;DR

This study experimentally investigates the Anderson localization transition for ultrasound in 3D mesoglasses, demonstrating how transverse confinement varies across the transition and identifying the mobility edges precisely.

Contribution

It provides the first detailed experimental validation of the self-consistent theory of Anderson localization for classical waves in 3D open media.

Findings

Clear signatures of Anderson localization observed in ultrasound transmission

Quantitative agreement with the self-consistent theory of localization

Precise identification of mobility edges in 3D mesoglasses

Abstract

We report an in-depth investigation of the Anderson localization transition for classical waves in three dimensions (3D). Experimentally, we observe clear signatures of Anderson localization by measuring the transverse confinement of transmitted ultrasound through slab-shaped mesoglass samples. We compare our experimental data with predictions of the self-consistent theory of Anderson localization for an open medium with the same geometry as our samples. This model describes the transverse confinement of classical waves as a function of the localization (correlation) length, $\xi$ ($\zeta$), and is fitted to our experimental data to quantify the transverse spreading/confinement of ultrasound all of the way through the transition between diffusion and localization. Hence we are able to precisely identify the location of the mobility edges at which the Anderson transitions occur.