Chen Weijin, Wang Zhenyu, Gorkunov Maxim V, Qin Jiazheng, Wang Ruize, Wang Chaowei, Wu Dong, Chu Jiaru, Wang Xuehua, Kivshar Yuri, Chen Yang
Chinese Academy of Sciences Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, 230027 Hefei, China.
Department of Electrical and Computer Engineering, National University of Singapore, 117583 Singapore, Singapore.
Nano Lett. 2024 Aug 7;24(31):9643-9649. doi: 10.1021/acs.nanolett.4c02402. Epub 2024 Jul 23.
Chiral nanostructures allow engineering of chiroptical responses; however, their design usually relies on empirical approaches and extensive numerical simulations. It remains unclear if a general strategy exists to enhance and maximize the intrinsic chirality of subwavelength photonic structures. Here, we suggest a microscopic theory and uncover the origin of strong chiral responses of resonant nanostructures. We reveal that the reactive helicity density is critically important for achieving maximum chirality at resonances. We demonstrate our general concept on the examples of planar photonic crystal slabs and metasurfaces, where out-of-plane mirror symmetry is broken by a bilayer design. Our findings provide a general recipe for designing photonic structures with maximum chirality, paving the way toward many applications, including chiral sensing, chiral emitters and detectors, and chiral quantum optics.
手性纳米结构能够实现旋光响应的工程设计；然而，其设计通常依赖于经验方法和大量的数值模拟。目前尚不清楚是否存在一种通用策略来增强和最大化亚波长光子结构的固有手性。在此，我们提出一种微观理论并揭示共振纳米结构强手性响应的起源。我们发现，反应性螺旋度密度对于在共振时实现最大手性至关重要。我们以平面光子晶体平板和超表面为例展示了我们的通用概念，其中通过双层设计打破了面外镜像对称性。我们的研究结果为设计具有最大手性的光子结构提供了一个通用方法，为许多应用铺平了道路，包括手性传感、手性发射器和探测器以及手性量子光学。
