Coexisting valley and pseudo-spin topological edge states in photonic topological insulators made of distorted Kekule lattices  

作　　者：Guochao Wei Zhenzhen Liu Licheng Wang Jianyuan Song Jun-Jun Xiao 

机构地区：[1]Shenzhen Engineering Laboratory of Aerospace Detection and Imaging,College of Electronic and Information Engineering,Harbin Institute of Technology(Shenzhen),Shenzhen 518055,China [2]Shenzhen Suntak Multilayer PCB Co.,Ltd.,Shenzhen 518115,China

出　　处：《Photonics Research》2022年第4期999-1010,共12页光子学研究（英文版）

基　　金：Shenzhen Science and Technology Program(JCYJ20210324132416040);National Key R&D Program of China(2018YFB1305500).

摘　　要：Photonic topological insulators protected by the lattice spatial symmetry(e.g., inversion and rotation symmetry)mainly support single type edge state, interpreted by either valley or pseudo-spin. Here, we demonstrate theoretically, numerically, and experimentally that a type of judiciously designed two-dimensional Kekulé photonic crystal with time reversal symmetry can possess topological valley and pseudo-spin edge states in different frequency bands. Topologically robust transportation of both the valley and pseudo-spin edge states was confirmed by measuring the transmission of straight and z-shaped interface supported edge mode and comparing with bulk modes in the microwave frequency regime. In addition, we show that due to the distinct topological origins, valley and pseudo-spin edge states can be distinguished by examining their end-scattering into the free space. Our system provides an alternative way in manipulating electromagnetic waves with additional degree-of-freedom, which has potential applications for robust and high-capacity waveguiding and multi-mode dividing.

关 键 词：TOPOLOGICAL SYMMETRY INSULATOR 

分 类 号：O469[理学—凝聚态物理]