论文标题
几何 - 瞬间诱导的非词性光子晶体中的高阶拓扑绝缘子
Geometric-anisotropy induced high-order topological insulators in nonsymmorphic photonic crystals
论文作者
论文摘要
在很大程度上，光子晶体的丰富物理特性取决于基础几何形状，其中组成的对称算子及其组合有助于表征拓扑阶段的独特拓扑不变。特别是，二维（2D）Su-Schrieffer-Heeger模型中的耦合和内部偶联调制产生拓扑相变，并显示一阶边缘局部局部状态和二阶角局部局部角状态。在这项工作中，我们将几何各向异性用于由四个矩形块组成的2D平方晶格。我们在设计的非形态光子晶体（PC）中显示了多种拓扑相变，这些过渡应从合成空间中的Zak阶段和Chern数字以及Pseudospin-2概念中理解。此外，周期性合成参数空间中的Zak相绕组产生高阶Chern数和双接口状态。基于扩展的Zak阶段和伪旋转厅效应，PC系统中构建了高阶拓扑绝缘子。相应的三维PC平板中也持续了有趣且丰富的拓扑特征，这使其成为控制光学信号流的非常有趣的平台。
To a significant extent, the rich physical properties of photonic crystals are determined by the underlying geometry, in which the composed symmetry operators and their combinations contribute to the unique topological invariant to characterize the topological phases. Particularly, the inter- and intra-coupling modulation in the two-dimensional (2D) Su-Schrieffer-Heeger model yields the topological phase transition, and exhibit first-order edge localized states and second-order corner localized corner states. In this work, we use the geometric anisotropy into the 2D square lattice composed of four rectangle blocks. We show a variety of topological phase transitions in designed nonsymmorphic photonic crystals (PCs) and these transitions shall be understood in terms of the Zak phase and Chern number in synthetic space, as well as the pseudospin-2 concept, combinationally. Furthermore, Zak phase winding in the periodic synthetic parameter space yields high-order Chern number and double interface states. Based on the extended Zak phase and pseudo-spin Hall effect, higher-order topological insulator is constructed in the PC system. The intriguing and abundant topological features are also sustained in the corresponding three-dimensional PC slab, which makes it a very interesting platform to control the flow of optical signals.
