发表机构
Swiss Federal Institute of Technology Lausanne (EPFL)（洛桑联邦理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文研究支持对称保护型BIC的混合等离激元-光子谐振波导光栅，指出数值模拟中荧光相关陷阱，发现BIC虽可抑制辐射泄漏但会引发欧姆损耗，为相关周期纳米光子系统的荧光等过程提供一致解释框架。
AI 中文摘要
连续介质中的束缚态（BIC）兼具高品质因子与强电磁场局域特性，因此被广泛用于增强光与物质的相互作用。然而，大场振幅并不能直接转化为两个供体-受体荧光团之间有用的荧光增强或能量转移增强。本文针对支持对称保护型BIC的混合等离激元-光子谐振波导光栅研究该问题，强调数值模拟中与荧光相关的一些陷阱，尤其是周期性边界条件的使用。与BIC相关的强场可增强受体吸收，但有用的荧光增强仍较为温和。大量模拟及不同品质因数的比较表明，虽然BIC可抑制辐射泄漏，但也会将大部分能量重定向为欧姆损耗。因此，供体的有用荧光增强仍较为温和，而在Förster共振能量转移（FRET）实验中，受体的吸收可被大幅增强。必须将近场FRET与长程能量转移及再吸收机制区分开，后两者均由离域BIC模式介导。最后，将有限光栅的结果与无限周期模拟进行比较，并解释了概念上的不一致。本工作为解释基于BIC的周期纳米光子系统中的荧光、吸收和能量转移提供了一致的框架。
英文摘要
Bound states in the continuum (BICs) combine high quality factors with strong electromagnetic-field localization and are therefore widely explored for enhancing light--matter interactions. However, large field amplitudes do not directly translate into useful fluorescence enhancement or energy transfer enhancement between two donor--acceptor fluorophores. Here, we investigate this question for a hybrid plasmonic--photonic resonant waveguide grating supporting a symmetry-protected BIC. We emphasize some of the pitfalls associated with the numerical simulations, especially the utilization of periodic boundary conditions for fluorescence. Strong BIC-related fields can enhance acceptor absorption while useful fluorescence enhancement remains moderate. Extensive simulations and the comparison of different figures of merit, indicate that, while a BIC can suppress radiative leakage, it can also redirect a large fraction of the energy into Ohmic losses. As a result, the useful fluorescence enhancement of donors remains moderate, whereas absorption by acceptors can be strongly enhanced in Förster resonance energy transfer (FRET) experiments. It is essential to separate near-field FRET from long-range energy transfer and reabsorption mechanisms, both of which are mediated by the delocalized BIC mode. Finally, results obtained for finite gratings are compared with infinite periodic simulations and conceptual inconsistencies explained. This work provides a consistent framework for interpreting fluorescence, absorption, and energy transfer in BIC-based periodic nanophotonic systems.
