Non-Hermitian metasurface with non-trivial topology
Non-Hermitian metasurface with non-trivial topology
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DOI：
10.1515/nanoph-2021-0731
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发表时间：
2022-02
期刊：
影响因子：
7.5
通讯作者：
Frank Yang;Ciril S. Prasad;Weijian Li;Rosemary Lach;H. Everitt;G. Naik
中科院分区：
文献类型：
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作者：
Frank Yang;Ciril S. Prasad;Weijian Li;Rosemary Lach;H. Everitt;G. Naik
摘要光子学中拓扑结构和非厄米性之间的协同作用为下一代抗缺陷的光学器件提供了巨大的潜力。然而，大多数非厄米和拓扑光子学的演示已被限制到超波长尺度，由于在深亚波长尺度的辐射损耗增加。通过仔细设计在纳米尺度上的辐射损耗，我们证明了一个非厄米等离子体介电元表面在可见光与非平凡的拓扑结构。元表面基于四阶无源奇偶时间对称系统。所设计的器件在其动量空间中呈现出一个特殊的同心环，并由具有非厄米Z 3 ${\mathbb{Z}}_{3}$拓扑不变量V = −1的哈密顿量描述。使用傅立叶空间成像进行单次拍摄k空间测量来表征制造的器件。我们的研究结果展示了一种将联合收割机拓扑结构和非厄米特纳米光子学相结合的方法，用于设计具有新功能的鲁棒器件。
Abstract The synergy between topology and non-Hermiticity in photonics holds immense potential for next-generation optical devices that are robust against defects. However, most demonstrations of non-Hermitian and topological photonics have been limited to super-wavelength scales due to increased radiative losses at the deep-subwavelength scale. By carefully designing radiative losses at the nanoscale, we demonstrate a non-Hermitian plasmonic–dielectric metasurface in the visible with non-trivial topology. The metasurface is based on a fourth order passive parity-time symmetric system. The designed device exhibits an exceptional concentric ring in its momentum space and is described by a Hamiltonian with a non-Hermitian Z 3 ${\mathbb{Z}}_{3}$ topological invariant of V = −1. Fabricated devices are characterized using Fourier-space imaging for single-shot k-space measurements. Our results demonstrate a way to combine topology and non-Hermitian nanophotonics for designing robust devices with novel functionalities.