光子狄拉克点及相关新特性研究

The physics of photonic bandgaps come from the electronic bandgaps. This project studies the new ways of manipulating photons that are inspired by the new electronic band structure (Dirac points). In photonic microstructures, the structural parameters can be flexibly tuned, which provides an ideal platform to study the physics，especially the new physics, of band structure. Based on the experimental platform of two-dimensional dielectric rod array in microwave regime, this project studies the connection between the new phenomena from the photonic band structure and the physics of electronic Dirac points, e.g., the connection between the photonic transport and the electronic transport around the Dirac points (energy valley) at Brillouin zone boundary, the connection between the zero refractive index and the Dirac points at Brillouin zone center. The contents of the project involve the cross between the optical physics and the condensed matter physics. Specifically, the project studies the control of the dispersion and the flow of photons by adjusting the internal and boundary structural parameters of the photonic graphene. The project also studies the scattering properties of zero-index materials based on the Dirac points at Brillouin zone center. Finally, the project studies the difference between the Dirac point at Brillouin zone center and that at Brillouin zone boundary. The study about the photonic Dirac points can not only help people make use of the new photonic band structure to control the flow of electromagnetic waves, but also plays a role in the applications and designs of waveguides and optical switches.

光子能带的物理来自电子能带，本项目研究新的电子能带结构（狄拉克点）带来的新的光子调控方法。光子微结构中结构参量易于调节，是研究能带物理、特别是新物理的理想平台。本项目以二维介质柱阵列作为微波段实验平台，研究光子能带结构新现象与电子狄拉克点物理之间的联系，如光子输运与布里渊区边界处狄拉克点（能谷）附近电子输运的联系，零折射率与布里渊区中心狄拉克点的联系。项目的研究内容涉及光物理和凝聚态物理的交叉，主要内容包括：调节光子石墨烯中内部和边界处的结构参数来调控光子的色散和传播特性；布里渊区中心狄拉克点实现的零折射率材料的散射特性；布里渊区中心和边界处狄拉克点之间的差别。对光子狄拉克点的研究不仅可以帮助人们利用新的光子能带结构来调控电磁波的运动，而且对导波和光学开关等相关器件的研制具有指导意义。

本项目研究了基于光子狄拉克点的能带调控新方法和新应用。 在二维介质柱和微带线实验平台的基础上，项目分别研究了布里渊区边界处的狄拉克点和布里渊区中心处的类狄拉克点的光场调控。在布里渊区边界处的狄拉克点方面，项目研究了光子石墨烯中谷依赖的电磁输运特性，包括谷光子束分光和由晶格形变产生的“人工磁场效应”。在布里渊区中心处的类狄拉克点方面，项目研究了基于类狄拉克点的零折射率材料中的光学纵模特性、类狄拉克点附近的拓扑转变特性和类狄拉克点处能隙反转形成的边缘态及光量子自旋霍尔效应。项目不仅研究了光子（类）狄拉克点附近的谷和拓扑等新物理，而且对谷光子束分离器、对厚度涨落不敏感的新型滤波器和对界面起伏不敏感的新型导波和分光器件的研制具有指导意义。