Simple theoretical model for parity-time-symmetric metasurfaces

Many new possibilities to observe and use novel physical effects are discovered at so called exceptional points (EPs). This is done by using parity-time (PT) -symmetric non-Hermitian systems and balancing gains and losses. When combined with EP-physics, recently, metasurfaces have shown greater abil...

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Bibliographic Details
Published inarXiv.org
Main Authors Xie, Jianlan, Dong, Shaohua, Yan, Bei, Peng, Yuchen, Liu, Jianjun, Qiu, Chengwei, Wen, Shuangchun
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 22.07.2021
Subjects
Circuits
Exact solutions
Finite element method
Gain-Loss
Incidence angle
Mathematical models
Metasurfaces
Model testing
Parity
Transfer matrices
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Summary:Many new possibilities to observe and use novel physical effects are discovered at so called exceptional points (EPs). This is done by using parity-time (PT) -symmetric non-Hermitian systems and balancing gains and losses. When combined with EP-physics, recently, metasurfaces have shown greater abilities for wave manipulation than conventional metasurface systems. However, the solving process for EPs usually requires the transfer matrix method (TMM) or a parametric sweep, which are both complex and time-consuming. In this Letter, we develop a simple theoretical model, which is based on acoustic equivalent-circuit theory and can find the analytic solutions for EPs directly. As a proof of concept, PT-symmetric acoustic metasurfaces are studied to test the theoretical model, which enables unidirectional antireflection effects at EPs. In addition, finite element method (FEM) simulations are performed to study these EP solutions using the theoretical model for different mediums, wavelengths, angles of incidence, and gain-loss ratios. Our work offers a simple and powerful theoretical tool for designing PT-symmetric metasurfaces at EPs and may also be used for other classical wave systems.
ISSN:2331-8422