arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0801.0906physics.opticscond-mat.mes-hall
收藏

二维周期规则阵列中金属纳米粒子的集体等离子体激元模

Collective plasmonic modes of metal nano-particles in two-dimensional periodic regular arrays

Yu-Rong Zhen, Kin Hung Fung, C. T. Chan

摘要:

我们研究了点偶极描述下周期性二维(2D)阵列中金属纳米粒子的集体等离子体激元模式。作为一个开放的系统,二维阵列的全动态色散关系,通过一个有效的方法,给出了一个有效的极化率描述系统的集体响应。色散关系和模式质量同时与有效极化率的虚部有关,这既有单粒子响应的贡献,也有粒子间耦合的贡献。横向长程偶极相互作用主要由波项连同表示对共振频率的静态几何贡献的纯几何常数来控制。作为具体的例子,我们认为小银球排列在一个正方形的晶格。我们发现,在光锥内,横向准模具有相当高的模式质量,而两个面内模式显示出显着的辐射阻尼。在光线附近,我们观察到横向模和横向面内模的带与自由光子的强耦合,并且纵向面内模在光锥内表现出负的群速度。所有准模在光锥中的消失群速度被发现是二维金属纳米球密集阵列的本征性质。

英文摘要:

We investigate the collective plasmonic modes of metal nano-particles in periodic two-dimensional (2D) arrays within a point-dipole description. As an open system, the full-dynamic dispersion relations of the 2D arrays are obtained through an efficient method which gives an effective polarizability describing the collective response of a system. Both the dispersion relations and mode qualities are simultaneously related to the imaginary part of the effective polarizability, which has contributions from the single-particle response as well as the inter-particle coupling. The transversal long-range dipolar interaction is dominated by a wave term together with a purely geometrical constant representing the static geometrical contribution to resonant frequencies. As concrete examples, we considered small Ag spheres arranged in a square lattice. We find that inside the light-cone, the transverse quasi-mode has a reasonably high mode quality while the two in-plane modes show significant radiation damping. Near the light-line, we observe strong coupling with free photons for the bands of the transverse mode and the transversal in-plane mode, and the longitudinal in-plane mode exhibits a negative group-velocity inside the light-cone. Vanishing group velocities in the light-cone for all the quasi-modes are found to be intrinsic properties of the 2D metal nano-sphere dense arrays.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑