Homogeneous Dislocation-Induced Rainbow Concentrating for Elastic Waves

TL;DR

This paper experimentally demonstrates rainbow concentrating of elastic waves in a phononic crystal with a homogeneous dislocation defect, enabling wave localization and frequency routing for potential applications in energy and information technologies.

Contribution

It introduces a novel homogeneous dislocation defect in phononic crystals to achieve rainbow concentrating of elastic waves, verified through experiments.

Findings

Homogeneous dislocation induces interface states for wave trapping.

Rainbow concentrating is scalable and configurable in phononic crystals.

Potential applications include energy harvesting and acoustic manipulation.

Abstract

Defects play a crucial role in the physical properties of crystals, whether for classical or quantum systems. For example, in photonic/phononic crystals, defects can serve as precise guidance and localization of classical electromagnetic or mechanical waves. Rainbow concentrating, a recently proposed exotic wave localization [Phys. Rev. Lett. 126, 113902 (2021)] exploits defects to enable the collection and frequency routing of weak signals in real space. In this paper, using a solid-state phononic crystal (PnC) plate, we experimentally verify this phenomenon by deliberately infusing a homogeneous graded dislocation, i.e., a line defect, into the PnC. Two PnCs separated by the defect will breed deterministic interface states along with the defect, offering rainbow trapping and concentrating for elastic waves. Our PnC-based rainbow trappers and concentrators are scalable and configurable, promising for advancing applications like energy harvesting, information processing, and acoustofluidic manipulating.