Symmetry Breaking in Gold-Silica-Gold Multilayer Nanoshells
Symmetry Breaking in Gold-Silica-Gold Multilayer Nanoshells
复制标题
DOI：
10.1021/nn901743m
复制
发表时间：
2010-03-01
期刊：
影响因子：
17.1
通讯作者：
Drezek, Rebekah A.
中科院分区：
文献类型：
--
作者：
Hu, Ying;Noelck, Sterling J.;Drezek, Rebekah A.
我们提出了一个计算研究的金-二氧化硅-金多层纳米壳的等离子体性质与中心偏移。对称破缺，由于核心偏移，使得在同心几何形状中暗的等离子体共振可见。应用等离子体杂化理论，我们解释了这些共振的起源，从核和壳之间的原始和多极模式混合的相互作用。这种相互作用在高阶模式中引入了偶极矩，并显著提高了它们对光的耦合效率。为了阐明对称破缺效应，我们将几何不对称与表面电荷的不对称分布联系起来，并举例说明了高阶模的多极特性减少和偶极特性增加。模的相对振幅是通过表面电荷分布中偶极分量的目测定性地联系起来的。使用极化相关的表面电荷图，我们说明了两种不同的模式配置，尽管它们的光谱相似。我们进一步证明了随着共振波长红移响应较大的核心偏移，相对于散射，吸收增加的趋势。
We present a computational study of the plasmonic properties of gold-silica -gold-multilayer nanoshells with the core offset from the center. Symmetry breaking, due to the core offset, makes plasmon resonances that are dark in concentric geometries visible. Applying plasmon hybridization theory, we explain the origin of these resonances from the interactions of an admixture of both primitive and multipolar modes between the core and the shell. The interactions introduce a dipole moment into the higher order modes and significantly enhance their coupling efficiency to light. To elucidate the symmetry breaking effect, we link the geometrical asymmetry to the asymmetrical distribution of surface charges and demonstrate illustratively the diminishing multipolar characteristic and increasing dipolar characteristic of the higher order modes. The relative amplitudes of the modes are qualitatively related by visual examination of the dipolar component in the surface charge distributions. Using polarization-dependent surface charge plots, we illustrate two distinct mode configurations despite their spectral similarities. We further demonstrate a trend of increasing absorption relative to scattering as the resonant wavelength red shifts in response to a larger core offset.