Xiao He1,†,Donglin Liu1,†,Hongfei Wang2,Liheng Zheng1,Bo Xu3,Biye Xie2,4,Meiling Jiang1,Zhixin Liu1,Jin Zhang3,Minghui Lu2,Zheyu Fang1
Abstract:Photonic topological insulators with robust boundary states can enable great applications for optical communication and quantum emission, such as unidirectional waveguide and single-mode laser. However, because of the diffraction limit of light, the physical insight of topological resonance remains unexplored in detail, like the dark line that exists with the crystalline symmetry-protected topological edge state. Here, we experimentally observe the dark line of theZ2 photonic topological insulator in the visible range by photoluminescence and specify its location by cathodoluminescence characterization, and elucidate its mechanism with the p-d orbital electromagnetic field distribution which calculated by numerical simulation. Our investigation provides a deeper understanding ofZ2 topological edge states and may have great significance to the design of future on-chip topological devices.
Opto-Electron Advances 5, 210015 (2022). 
oea-2021-0015-fangzheyu.pdf
