Level repulsion and evanescent waves in sonic crystals

TL;DR

This paper combines theoretical and experimental approaches to analyze evanescent waves and level repulsion in sonic crystals, revealing complex band structures that enable control over wave propagation in periodic acoustic materials.

Contribution

It introduces a comprehensive method to interpret evanescent modes and level repulsion states using complex band structures, advancing understanding of wave control in sonic crystals.

Findings

Evanescent modes predicted beyond classical methods.

Complex band structures explain propagation properties.

Control of evanescent waves demonstrated.

Abstract

This work theoretically and experimentally reports the evanescent connections between propagating bands in periodic acoustic materials. The complex band structures obtained by solving for the $k(\omega)$ problem reveal a complete interpretation of the propagation properties of these systems. The prediction of evanescent modes, non predicted by classical $\omega(\vec{k})$ methods, is of interest for the understanding of these propagation properties. Complex band structures provide an interpretation of the evanescent coupling and the level repulsion states showing the possibility to control of evanescent waves in periodic materials.