非厄米光学系统的动态环绕奇异点研究

非厄米光学系统因其非厄米自由度的存在，展示了损耗诱导透射增强、非对称模式转化等新奇的物理效应和现象，为操控光子提供了新手段。这一系统最重要的特征是奇异点，但目前围绕该领域重要前沿方向之一的动态环绕奇异点的研究仍然局限于低阶奇异点、宇称-时间（Parity-time, PT）对称系统、以及微波波段，具有重要应用价值的高阶奇异点、反PT对称系统、光通信波段的研究基本上还是空白领地。针对这一不足，本项目提出三阶奇异点动态环绕的理论/实验方案，揭示高阶奇异点的拓扑结构以及动态环绕特性；提出基于硅基光波导的光波实验平台，通过设计反PT对称系统，利用其独特的拓扑结构，实现在PT对称系统中无法实现的应用−将对称性破缺模式应用到非对称模式转化。由此揭示非厄米光学系统的新物理，推动非厄米物理在光子调控领域的新应用。

Non-Hermitian optical systems exhibit novel physical phenomena such as loss induced transmission enhancement and asymmetric mode switching due to the presence of non-Hermiticity, leading to new photon manipulation strategies. The most important feature of non-Hermitian systems is the exceptional point (EP). However, most of the current researches related to the dynamical encircling of the EP focus on low-order EPs, parity-time (PT) symmetric systems and microwave regimes. The researches on high-order EPs, anti-PT symmetric systems and optical regimes, which are also important for non-Hermitian applications, are yet to be investigated. Aiming at the above shortcoming, this project proposes the theory and experiment of dynamically encircling a third-order EP and reveal the topological structure of non-Hermitian systems possessing high-order EPs. The project also proposes a silicon-on-insulator non-Hermitian platform, on which we study the dynamical encircling of the EP in anti-PT symmetric systems and realize the asymmetric mode switching for symmetry-broken modes, which is an application unique to anti-PT symmetric systems and cannot be achieved in conventional PT symmetric systems. The project will reveal new physics of non-Hermitian systems and propose new non-Hermitian applications for photon manipulations.