北京应用物理与计算数学研究所张伟团队近日研究了纳米颗粒复合物中的等离子体激元杂交与电荷转移等离子体激元：等效电路模型方法。这一研究成果发表在2025年7月17日出版的《物理评论A》杂志上。

在多功能光学纳米电路的信号处理中，纳米粒子复合物的等离子体激振耦合对电路的响应起着重要的作用。

研究组建立了一个基于环路矩阵方法的等效电路模型来探讨纳米棒复合物中的耦合效应。在时域有限差分模拟的支持下，他们的分析结果不仅同时给出了（筛选）键模式、反键模式和电荷转移等离子体（CTP）模式的共振特征，还揭示了筛选键偶极等离子体（BDP）和CTP具有共同起源（多极等离子体模式残余）的物理画面。

研究组发现，CTP的共振波长敏感地依赖于连接纳米棒的导电电桥的长度，与基于BDP的测量相比，CTP的测量灵敏度提高了10倍，而随着电桥宽度的改变，远场散射模式也发生了变化。此外，还发现了粒子间耦合诱导的Rabi分裂、Fano效应和双CTP。该工作为研究纳米复合材料的电磁耦合机理提供了新的分析视角，为纳米电路和微纳米光学器件的设计奠定了基础。

附：英文原文

Title: Plasmon hybridization and the charge-transfer plasmon in a nanoparticle complex: An equivalent circuit model approach

Author: Yifan Zhi, Wei Zhang

Issue&Volume: 2025/07/17

Abstract: The coupling among plasmonic excitations of the nanoparticle complex plays an important role in the responses of optical nanocircuits with multifunction in signal processing. We develop an equivalent circuit model based on the loop matrix method to explore the coupling effects in the complex of nanorods. Our analytical results supported by finite-difference time-domain simulations not only give the resonance characters of (screening) bonding mode, antibonding mode, and charge-transfer plasmon (CTP) mode simultaneously, but also reveal the physics picture of the screening bonding dipole plasmon (BDP) and CTP with common origin (the remnants of multipole plasmonic modes). It is found that the resonance wavelength of the CTP depends sensitively on the length of the conductive bridge connecting the nanorods, showing factor 10 enhancement of measurement (of the interparticle gap size) sensitivity as a nanoruler compared with that based on the BDP, while with changing the bridge width there is a switch of the mode nature with associated change of far-field scattering patterns. In addition, interparticle coupling induced Rabi splitting, Fano effect, and dual CTPs have been found. Our studies provide a new analytical perspective on the electromagnetic coupling mechanism of nanocomposites and establish a foundation for the design of nanocircuits and micro-nano-optical devices.

DOI: 10.1103/p6pq-lhw1

Source: https://journals.aps.org/pra/abstract/10.1103/p6pq-lhw1