Jiang Zhen, Gao Yongfeng, He Liu, Song He, Zhou Jun, Zhu Renjie
Appl Opt. 2019 Mar 20;58(9):2294-2299. doi: 10.1364/AO.58.002294.
Topologically protected edge states of honeycomb photonic crystals (PCs) have been extensively studied in recent years. Here we propose several optimized two-dimensional PC configurations with distinct line defects introduced by breaking the C symmetry of each topological lattice along the interfaces between two different topologies. The spin-flipping nature of the defect modes of these PC configurations is measured, which is expected to offer a novel realization mechanism of quantum spin Hall effect. The line defects can be treated as unidirectional air waveguides due to the characteristic topological properties. We manipulate the coupling effect of two helical edge states with tunable waveguide widths. It shows that the air waveguide has possibility for practical applications because of its suppression of backward scattering and considerable transmission efficiency.
近年来，蜂窝状光子晶体（PCs）的拓扑保护边缘态受到了广泛研究。在此，我们提出了几种优化的二维PC结构，通过沿两种不同拓扑结构之间的界面打破每个拓扑晶格的C对称性引入了独特的线缺陷。测量了这些PC结构缺陷模式的自旋翻转特性，预计这将为量子自旋霍尔效应提供一种新颖的实现机制。由于其独特的拓扑性质，线缺陷可被视为单向空气波导。我们通过可调的波导宽度来操控两个螺旋边缘态的耦合效应。结果表明，空气波导由于其对背向散射的抑制和可观的传输效率而具有实际应用的可能性。
