光的拓扑绝缘体及其物理特性研究：在光子晶体表面控制光

Motivated by investigations on topological insulators for electrons, we have recently constructed a three-dimensional photonic crystal (PC) slab and found Dirac-cone photonic surface states by using an exact multiple-scattering method in conjunction with supercell calculations, which the transmission properties of electromagnetic waves near the Dirac point on the surface of the sample are similar to the case of electrons on the surfaces of topological insulators. This means that "three-dimensional optical topological insulators" can be designed. Based on such an investigation, in the present application we will study on some novel physical properties of waves transport in "optical topological insulators". The negative refraction, self-collimation and superfocusing of the surface wave will be investigated; The physical origin of the surface wave scattered by the magnetic impurity and the possibility of anomalous optical Hall effect will be discussed; The slow light effect and improved nonlinear response will be also analyzed; The single optical functional device and integrated optical circuit will be also designed. Based on these investigations, a new train of thought can be provided for the design of optical-electronic devices.

在电子拓扑绝缘体研究的启发下，最近我们通过严格的数值模拟证明经过适当设计Dirac谷型光表面态能够在三维光子晶体表面上观察到，表面波在Dirac谷附近传播拥有电子在三维拓扑绝缘体中传输相似的特性。这意味着与三维电子拓扑绝缘相对应的"光拓扑绝缘体"能够被设计出来。基于这样的研究基础，本申请主要是对波在"光拓扑绝缘体"中传播出现的新奇物理特性进行研究。研究表面波在光子晶体表面传导的负折射、自准直和超聚集现象；探讨表面波被磁性杂质散射的物理机理和出现反常光霍尔效应的可能性；研究表面波在光子晶体表面传导的慢光效应和提高的非线性反应；探讨在光子晶体表面构造单个光学功能元件和集成光回路的可能性。通过对表面波在光子晶体表面传播出现的新奇物理现象研究，为微光电子器件的研制和开发提供新的思路。

本项目以“光拓扑绝缘体”(特殊光子晶体)为研究背景,研究如何在表面和介面来控制光。我们首先设计出了一些三维光子晶体结构, 在其表面观察到了Dirac谷表面态; 设计出了介电球组成的单层结构,观察到了自相似的巨光自旋霍耳效应。基于此, 我们设计出了两种极化选择的光聚集棱镜。在介质板和纳米结构界面实现了光连续模束缚态, 极大提升了石墨烯对光的吸收效率。对纳米结构和光子晶体表面非线性光调控进行了研究。在线性光子晶体和非线性光子晶体周期性交替排列形成的二维光子晶体异质结结构中,获得了高效的二次谐波产生; 在介电球单层结构中首次观察到了倍频场的光自旋分离和霍耳效应。发展出了计算手性分子和纳米球簇相互作用的多重散射和有限元方法，使之能够计算微纳结构和具有不同取向手性分子复合体系的光反应。基于这些方法我们对纳米结构表面激发模式与原子和分子相互作用进行了研究, 设计出了多qubit量子相门等量子器件, 实现了对量子态调控。