Space-and frequency-division multiplexing in photonic second-order topological insulators  

作　　者：GUANGXU SU RENWEN HUANG SHIYIN JIA JIANGLE HE ZHIXIN SONG JUNZHENG HU MINGHUI LU FANXIN LIU PENG ZHAN 

机构地区：[1]Department of Applied Physics,Zhejiang University of Technology,Hangzhou 310023,China [2]National Laboratory of Solid State Microstructures,Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China

出　　处：《Photonics Research》2024年第10期2323-2333,共11页光子学研究（英文版）

基　　金：National Key Research and Development Program of China(2021YFA1401103,2022YFA1404302);National Natural Science Foundation of China(11834007,11974015,12174189,12304431);Natural Science Foundation of Zhejiang Province(LQ24A040015,LZ22A040008)。

摘　　要：Higher-order topological insulators,originally proposed in quantum condensed matters,have provided a new avenue for localizing and transmitting light in photonic devices.Nontrivial band topology in crystals with certain symmetries can host robust topological edge states and lower dimensional topological corner states(TCS),making them a promising platform for photonics applications.Here,we have designed several types of TCS with only two specific C6v-symmetric photonic crystals with various seamless splicing boundaries,where all the supposed TCS with diverse electromagnetic characteristics are visualized via numerical simulations and experimental measurements.More interestingly,we have observed that those TCS overlapping in spectral and spatial space tend to interweaved,inducing spectrum division.Meanwhile,the equivalent corners appear to have TCS with a phase difference,which is critical for directional activation of pseudospin dependence.Our findings demonstrate that coupled TCS with phase difference at different nanocavities can be selectively excited by a chiral source,which indicates that the TCS at this time have pseudospin-dependent properties.We further design a specific splicing structure to prevent coupling between adjacent TCS.This work provides a flexible approach for space-and frequency-division multiplexing in photonic devices.

关 键 词：properties TOPOLOGICAL INSULATOR 

分 类 号：O431.2[机械工程—光学工程]