谷光子晶体中拓扑界面态、谷霍尔效应及相关器件研究

Photonic crystal provides an unprecedented opportunities for photons manipulation and application. In recent years, the concept of “valley” and "topology" has been introduced to photonic crystal. This can expand the ranges of photons manipulation and application. Valley photonic crystal is a kind of particular photonic crystal with valley pseudospin state, which can open a new route of photons manipulation with valley related topological property. In this project, we will study the novel physics mechanism of valley topological controlled electromagnetic transport behavior in valley photonic crystal based on microwave experimental platform. The project mainly includes three aspects. Firstly, we will experimentally study topological edge states in valley photonic crystals by constructing valley photonic crystal with different valley Chern number. Thereby we will reveal the physics mechanism of valley related topology edge states protected by valley topological phase transition; Secondly, we will experimentally study topology induced valley hall effect. Through constructing different topology structures with nonzero topological charge, we can study the topology hall edge states that vary with different incident directions. Moreover, we can qualitatively reveal the relationship between the valley hall effect and topological structures as well as the incident angles of electromagnetic waves. Thirdly, we will explore potential applications of the valley related topological transport properties and valley hall effect for valley photonic crystals in optical devices. For example, we can realize topology valley transport with non-backscattering and design topological protected one-way transmission photonic devices that with defects insensitive functions. The research of these topics will not only deepen the understanding of the basic physics process for valley related topological transport, but also provides a scientific basis for related applications of valley photonic crystal in the development of future photonic devices.

光子晶体为光子操控及其应用提供了前所未有的机遇。将谷和拓扑概念运用到光子晶体中，可以进一步拓展光子操控方式及其应用范围。谷光子晶体是一类具有谷赝自旋态的特殊光子晶体结构，可以实现谷相关拓扑特性的光子操控新途径。本项目拟借助微波实验平台研究谷光子晶体中谷拓扑调控电磁输运的新奇物理机制。主要包括以下三个方面：谷光子晶体中谷拓扑界面态的实验研究，通过构建具有不同谷陈数的谷光子晶体，揭示受拓扑相变保护的谷拓扑边界态的物理机理；拓扑诱导谷霍尔效应的实验研究，构建具有不同非零拓扑电荷的拓扑结构，研究随入射方向变化的拓扑霍尔边界态，揭示谷霍尔效应与拓扑结构及入射角之间的定性关系；利用谷光子晶体实现无反射的拓扑谷输运，进而设计具有拓扑保护的光子单向传输器件。上述问题的研究，不仅会加深人们对谷光子晶体拓扑界面态、谷霍尔效应基本物理过程的理解，而且可以为谷光子晶体的应用研究及新型光子器件的研制提供科学依据。

本项目主要研究了光子晶体及相关电磁人工微结构实现对电磁波的操控、拓扑与谷相关奇异物理现象的观测、光学功能器件的设计及相关应用研究。主要包含以下几点：利用拓扑相变超材料操纵电磁波，提出一种利用零折射超材料透镜产生贝塞尔光束的新方法；利用拓扑界面态与表面局域态相互作用实现双向完美吸收；通过可变折射率人工微结构操控空间波和表面波的传播；实现了级联的类电磁感应透明效应，并借助可变电容器实现了电磁感应透明效应的主动控制；实现了基于平能带的电磁感应透明效应，并观察到强的慢光（群延迟）作用；设计并研制了一套具有可控旋转的机械可编程功能的智能超表面电磁波主动控制系统；皮尔西-高斯光束在自由空间中的双自聚焦行为研究; 此外，在相关应用研究方面，将人工磁导体应用于无线能量传输系统，将PT对称人工微结构应用于超灵敏折射率传感系统，将电子自旋材料应用于新型电子器件。