Zhang Zhenghe, Xu Chaojie, Liu Chen, Lang Man, Zhang Yuehao, Li Minghao, Lu Wanli, Chen Zefeng, Wang Chinhua, Wang Shaojun, Li Xiaofeng
School of Optoelectronic Science and Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, China.
Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006, China.
Nano Lett. 2023 Aug 23;23(16):7584-7592. doi: 10.1021/acs.nanolett.3c02148. Epub 2023 Aug 4.
Optical bound states in the continuum (BICs) offer strong interactions with quantum emitters and have been extensively studied for manipulating spontaneous emission, lasing, and polariton Bose-Einstein condensation. However, the out-coupling efficiency of quasi-BIC emission, crucial for practical light-emitting devices, has received less attention. Here, we report an adaptable approach for enhancing quasi-BIC emission from a resonant monocrystalline silicon (c-Si) metasurface through lattice and multipolar engineering. We identify dual-BICs originating from electric quadrupoles (EQ) and out-of-plane magnetic dipoles, with EQ quasi-BICs exhibiting concentrated near-fields near the c-Si nanodisks. The enhanced fractional radiative local density of states of EQ quasi-BICs overlaps spatially with the emitters, promoting efficient out-coupling. Furthermore, coupling the EQ quasi-BICs with Rayleigh anomalies enhances directional emission intensity, and we observe inherent opposite topological charges in the multipolarly controlled dual-BICs. These findings provide valuable insights for developing efficient nanophotonic devices based on quasi-BICs.
连续域中的光学束缚态（BICs）与量子发射器具有强相互作用，并且已经被广泛研究用于操纵自发辐射、激光发射和极化激元玻色-爱因斯坦凝聚。然而，对于实际发光器件至关重要的准BIC发射的外耦合效率却较少受到关注。在此，我们报告了一种通过晶格和多极工程增强共振单晶硅（c-Si）超表面准BIC发射的适应性方法。我们识别出源自电四极子（EQ）和面外磁偶极子的双BIC，其中EQ准BIC在c-Si纳米盘附近表现出集中的近场。EQ准BIC增强的分数辐射局域态密度在空间上与发射器重叠，促进了高效的外耦合。此外，将EQ准BIC与瑞利异常耦合增强了定向发射强度，并且我们在多极控制的双BIC中观察到固有的相反拓扑电荷。这些发现为基于准BIC开发高效纳米光子器件提供了有价值的见解。
