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arXiv · 2205.14824

Anomalous Floquet non-Hermitian skin effect in a ring resonator lattice

He Gao·Haoran Xue·Zhongming Gu·Linhu Li·Weiwei Zhu·Zhongqing Su·Jie Zhu·Baile Zhang·Y. D. Chong
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Abstract

We present a one-dimensional coupled ring resonator lattice exhibiting a variant of the non- Hermitian skin effect (NHSE) that we call the anomalous Floquet NHSE. Unlike existing approaches to achieving the NHSE by engineering gain and loss on different ring segments, our design uses fixed on-site gain or loss in each ring. The anomalous Floquet NHSE is marked by the existence of skin modes at every value of the Floquet quasienergy, allowing for broadband asymmetric transmission. Varying the gain/loss induces a non-Hermitian topological phase transition, reversing the localization direction of the skin modes. An experimental implementation in an acoustic lattice yields good agreement with theoretical predictions, with a very broad relative bandwidth of around 40%.

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He Gao, Haoran Xue, Zhongming Gu, Linhu Li, Weiwei Zhu, Zhongqing Su, Jie Zhu, Baile Zhang, Y. D. Chong. 2022-09-28. Anomalous Floquet non-Hermitian skin effect in a ring resonator lattice. https://doi.org/10.1103/physrevb.106.134112

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