Isobe Takuma, Yoshida Tsuneya, Hatsugai Yasuhiro
Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki, Japan.
Department of Physics, Kyoto University, Kyoto, Japan.
Nanophotonics. 2023 Jun 12;12(13):2335-2346. doi: 10.1515/nanoph-2022-0747. eCollection 2023 Jun.
Non-Hermitian topological band structures such as symmetry-protected exceptional rings (SPERs) can emerge for systems described by the generalized eigenvalue problem (GEVP) with Hermitian matrices. In this paper, we numerically analyze a photonic crystal with negative index media, which is described by the GEVP with Hermitian matrices. Our analysis using COMSOL Multiphysics demonstrates that a SPER emerges for photonic crystals composed of split-ring resonators and metal-wire structures. We expect that the above SPER can be observed in experiments as it emerges at a finite frequency.
对于由厄米矩阵的广义特征值问题（GEVP）描述的系统，诸如对称保护的例外环（SPER）之类的非厄米拓扑能带结构可能会出现。在本文中，我们对具有负折射率介质的光子晶体进行了数值分析，该光子晶体由厄米矩阵的GEVP描述。我们使用COMSOL Multiphysics进行的分析表明，由裂环谐振器和金属线结构组成的光子晶体会出现一个SPER。我们预计上述SPER可以在实验中被观测到，因为它出现在有限频率处。
