等离子体增强荧光的旋转体有限元模型
Body-of-Revolution Finite-Element Model of Plasmon-Enhanced Fluorescence
AI总结：
本研究提出旋转体有限元方法（BOR-FEM），用于高效建模轴对称及可等效轴对称的非轴对称等离子体增强荧光体系，揭示了壳厚对工作模式的影响，其预测结果与实验吻合良好，为相关生物纳米光子体系设计提供了实用途径。
AI中文摘要：
等离子体增强荧光（PEF）是发射器与等离子体纳米天线混合体系中研究最广泛的光学现象之一，应用范围从生物传感到单分子发射显微镜。本研究采用旋转体有限元方法（BOR-FEM），将PEF的有限元建模扩展到球对称几何之外的体系。通过利用精确或等效旋转对称性，将三维发射器-纳米天线体系简化为计算高效的二维形式，同时保留决定激发和发射过程的关键电磁相互作用。我们将该框架与三个已研究的发射器-纳米棒体系（包括一个需要等效轴对称几何变换的体系）进行验证，随后将其应用于发射器-核壳纳米棒体系。具体而言，我们研究了植物主要捕光复合物（LHCII，地球上最丰富的膜蛋白）的末端叶绿素发射器，与具有一个或两个介电壳的金核-介电壳纳米天线相互作用时的PEF。模拟结果表明，激发增强、辐射速率增强与非辐射欧姆损耗之间的相互作用产生了四种不同的、依赖于壳厚的工作模式：猝灭、增强、抑制和解耦，其中解耦模式下可恢复本征量子产率。预测的实验相关双壳纳米天线的增强因子与之前报道的测量结果吻合良好。这些结果确立了BOR-FEM是一种高效且通用的框架，适用于轴对称纳米天线几何及可等效为轴对称的非轴对称几何中的PEF建模，为等离子体增强生物纳米光子体系的合理设计与优化提供了实用途径。
英文摘要：
Plasmon-enhanced fluorescence (PEF) is one of the most widely investigated optical phenomena in hybrid systems of emitters and plasmonic nanoantennas, with applications ranging from biosensing to single-molecule emission microscopy. In this work, we extend finite-element modelling of PEF beyond spherically symmetric geometries using a body-of-revolution finite-element method (BOR-FEM). By exploiting exact or equivalent rotational symmetry, 3D emitter-nanoantenna systems are reduced to computationally efficient 2D formulations while retaining the essential electromagnetic interactions governing excitation and emission. We validate the framework against three previously investigated emitter-nanorod systems, including one requiring an equivalent axisymmetric geometric transformation, before applying it to an emitter-core-shell nanorod system. Specifically, we investigate the PEF of the terminal chlorophyll emitter of the major plant light-harvesting complex (LHCII), the most abundant membrane protein on Earth, interacting with a gold core-dielectric shell nanorod with one or two dielectric shells. The simulations reveal that the interplay between excitation enhancement, radiative-rate enhancement, and non-radiative Ohmic losses gives rise to four distinct shell-thickness-dependent operating regimes (quenching, enhancement, suppression, and decoupling), with recovery of the intrinsic quantum yield in the decoupling regime. The predicted enhancement factors for experimentally relevant dual-shell nanorods agree well with previously reported measurements. These results establish BOR-FEM as an efficient and versatile framework for modelling PEF in rotationally-symmetric nanoantenna geometries and in non-axisymmetric geometries that admit equivalent axisymmetric representations, providing a practical route for the rational design and optimisation of plasmon-enhanced bio-nanophotonic systems.
