Geng Ye, Yang Biao
Opt Lett. 2024 Dec 1;49(23):6641-6644. doi: 10.1364/OL.541308.
In the past decade, there has been a significant surge of interest in investigating non-Hermitian Hamiltonians, particularly in photonics. The eigenvalues of general non-Hermitian Hamiltonians are complex and possess unique topological features such as exceptional degeneracy. The introduction of non-Hermitian perturbations into Weyl semimetals can transform Weyl points into exceptional rings characterized by multiple topological invariants. However, the ideal realization of Weyl rings within practical three-dimensional structures has remained a significant challenge. In this work, we extend artificial photonic metamaterial structures that can transform ideal Weyl points into non-Hermitian exceptional rings. We show the associated intriguing polarization-momentum ultrahigh absorption, which enables what we believe to be a new device application in non-Hermitian photonics. Our study not only proposes the practical model for ideal non-Hermitian photonic Weyl exceptional rings but also opens the gate of non-Hermitian scattering characterization.
在过去十年中，对非厄米哈密顿量的研究兴趣激增，尤其是在光子学领域。一般非厄米哈密顿量的本征值是复数，具有独特的拓扑特征，如例外简并。将非厄米微扰引入外尔半金属可以将外尔点转变为由多个拓扑不变量表征的例外环。然而，在实际三维结构中理想地实现外尔环仍然是一个重大挑战。在这项工作中，我们扩展了人工光子超材料结构，该结构可以将理想外尔点转变为非厄米例外环。我们展示了相关的有趣的偏振 - 动量超高吸收，这使我们相信能在非厄米光子学中实现一种新的器件应用。我们的研究不仅提出了理想非厄米光子外尔例外环的实际模型，还开启了非厄米散射表征的大门。
