Qian Zhiyuan, Li Zhichao, Hao He, Shan Lingxiao, Zhang Qi, Dong Jianwen, Gong Qihuang, Gu Ying
State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871, China.
State Key Laboratory of Optoelectronic Materials and Technologies and School of Physics, Sun Yat-sen University, Guangzhou 510275, China.
Phys Rev Lett. 2021 Jan 15;126(2):023901. doi: 10.1103/PhysRevLett.126.023901.
We propose the mechanism of edge state-led mode coupling under topological protection; i.e., localized surface plasmons almost do not have any influence on the edge state, while the edge state greatly changes the local field distribution of surface plasmons. Based on this mechanism, in the well-designed topological photonic structure containing a resonant plasmon nanoantenna, an obvious absorption reduction in the spontaneous emission spectra appears due to the near-field deformation around the antenna induced by the edge state. Because a plasmon antenna with ultrasmall mode volume provides large Purcell enhancement and simultaneously the photonic crystal guides almost all scattering light into its edge state, the rate of nonscattering single photons reaches more than 10^{4}γ_{0}. This topological state-led mode coupling mechanism and induced absorption reduction, which are based on topological protection, will have a profound effect on the study of composite topological photonic structures and related micro- and nanoscale cavity quantum electrodynamics. Also, nonscattering large Purcell enhancement will provide practical use for on-chip quantum light sources, such as single-photon sources and nanolasers.
我们提出了拓扑保护下边缘态主导的模式耦合机制；即局域表面等离子体激元几乎对边缘态没有任何影响，而边缘态极大地改变了表面等离子体激元的局部场分布。基于此机制，在精心设计的包含共振等离子体纳米天线的拓扑光子结构中，由于边缘态引起的天线周围近场变形，自发发射光谱中出现明显的吸收降低。由于具有超小模式体积的等离子体天线提供了大的珀塞尔增强，同时光子晶体将几乎所有散射光引导到其边缘态，非散射单光子的速率达到超过10⁴γ₀。这种基于拓扑保护的拓扑态主导的模式耦合机制和诱导吸收降低，将对复合拓扑光子结构及相关微纳尺度腔量子电动力学的研究产生深远影响。此外，非散射大珀塞尔增强将为片上量子光源，如单光子源和纳米激光器提供实际应用。
