近日，南开大学许京军团队报道了基于三维手性的非厄米系统在极压下实现了不对称极化开关和全极化作用。该项研究成果发表在2025年11月18日出版的《光：科学与应用》杂志上。

非厄米系统中的非对称模式/态切换与全偏振器功能已展现出应用潜力，这类现象通常需要在非厄米参数空间中进行缓慢的参数环绕过程方能实现。能否仅通过异常点（EP）而无需环绕过程来实现上述功能？

研究组提出利用三维手性材料构建非厄米系统，在异常点处直接实现上述功能。研究表明，该三维手性非厄米系统展现出与传统非厄米光学系统截然不同的特性：系统中前向与后向传播的本征态存在差异，从而实现非对称态切换；在异常点处，系统前向与后向传播的简并本征态相互正交，使系统具备全偏振器功能。

为验证理论，研究组提出一种普适性调控方法，可将三维手性非厄米系统从远离异常点的状态调控至异常点邻近区域。基于此，他们通过实验构建自由空间光学三维手性非厄米系统，直接观测了异常点附近光偏振态的演化过程。实验结果证实所提出的光学系统能在异常点实现非对称态切换与全偏振器功能，与理论预测完全一致。该研究为三维手性非厄米光学应用（如高灵敏度手性测量与偏振态操控）开辟了新路径。

附：英文原文

Title: Non-Hermitian systems based on 3D chirality enabled asymmetrical polarization switching and omni-polarizer action at an EP

Author: Fu, Xianhui, Hu, Hao, Zhang, Jiawei, Qi, Jiwei, Zhang, Sihao, Wu, Qiang, Lu, Yao, Chen, Zongqiang, Chen, Jing, Yu, Xuanyi, Sun, Qian, Xu, Jingjun

Issue&Volume: 2025-11-18

Abstract: Asymmetric mode/state switching and omni-polarizer action have demonstrated application potential and can be realized in non-Hermitian systems, which required a slow encircling process in the non-Hermitian parameter space in general. Is it possible to achieve the above functions only at an exceptional point (EP) without the encircling process Here, we propose constructing a non-Hermitian system using three-dimensional (3D) chiral materials to realize the above functions at an EP instead of through the encircling process. Our results show that the 3D chiral non-Hermitian system exhibits properties that are quite different from those of traditional non-Hermitian optical systems. In our system, the eigenstates are different when propagating forward and backward, thus enabling asymmetric state switching. At the EP, the degenerate eigenstates of forward and backward propagations of the system become mutually orthogonal, which enables the system to act as an omni-polarizer. Crucially, to validate our claims, we propose a straightforward and widely applicable method to adjust a 3D chiral non-Hermitian system from a state far from an EP to near an EP. Based on this, we construct a free-space optical 3D chiral non-Hermitian system experimentally to directly observe the evolution of light polarization states near the EP. The experimental results prove that the proposed optical systems can achieve asymmetric state switching and omni polarizers at the EP, which is consistent with our theoretical expectations. Our work holds promise for various 3D chiral non-Hermitian optical applications, such as highly sensitive chirality measurements and polarization manipulation.

DOI: 10.1038/s41377-025-01960-5

Source: https://www.nature.com/articles/s41377-025-01960-5