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arXiv · 1611.03258

Non-Hermitian Acoustic Metamaterials: the role of Exceptional Points in sound absorption

V. Achilleos·G. Theocharis·O. Richoux·V. Pagneux
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Abstract

Effective non-Hermitian Hamiltonians are obtained to describe coherent perfect absorbing and lasing boundary conditions. PT -symmetry of the Hamiltonians enables to design configurations which perfectly absorb at multiple frequencies. Broadened and flat perfect absorption is predicted at the exceptional point of PT -symmetry breaking while, for a particular case, absorption is enhanced with the use of gain. The aforementioned phenomena are illustrated for acoustic scattering through Helmholtz resonators revealing how tailoring the non-Hermiticity of acoustic metamaterials leads to novel mechanisms for enhanced absorption.

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V. Achilleos, G. Theocharis, O. Richoux, V. Pagneux. 2016-11-10. Non-Hermitian Acoustic Metamaterials: the role of Exceptional Points in sound absorption. https://doi.org/10.1103/physrevb.95.144303

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