Tuning the Dipolar Plasmon Hybridization of Multishell Metal-Dielectric Nanostructure: Gold Nanosphere in a Gold Nanoshell

Abstract

Because of the interaction between dipole resonances of the inner gold sphere and the outer gold shell, gold-dielectric-gold multishells with sub-50 nm diameter may at most have three hybridization modes of surface plasmon resonance (SPR). Theoretical calculations based on quasi-static theory indicate that there are blending and splitting of SPR bands in the absorption spectra, which makes the number of absorption peak tunable by changing the radius of inserted gold sphere, thickness of gold shell, dielectric constant of middle dielectric shell or outer environment. The two absorption peaks at longer wavelength, which correspond to the hybridization from the bonding shell plasmon and the sphere plasmon, are usually intense and well tunable. The absorption peak at shorter wavelength, which corresponds to the symmetric coupling between the anti-bonding shell plasmon and the sphere plasmon, is relative weak and only occurs with large dielectric constant of the middle shell, small dielectric constant of the outer surrounding, large inner radius of the gold shell, and small radius of the inner gold sphere. Furthermore, the physical origin of these plasmon hybridizations in gold-dielectric-gold multishells nanostructure has also been illuminated by analyzing the local electric field distributions.

Geometrical parameters controlled focusing and enhancing near field in infinite circular metal-dielectric multilayered cylinder

“…From high to low energy, the first hybridization plasmon mode denoted as jx þ þ i is corresponding to anti-symmetric coupling between the anti-bonding tube plasmon mode and the inner wire plasmon. 31,32 Because the inner wire plasmon is oppositely aligned with the outer tube plasmon and further weakens the dipole moment of jx þ þ i mode, the plasmon peak corresponding to jx þ þ i mode is usually too weak to be observed. The second hybridization mode denoted as jx À þ i is corresponding to symmetric coupling between the anti-bonding outer tube plasmon mode and the inner wire plasmon.…”

“…As is known that the jx À À i hybridization mode is an antisymmetric coupling between the bonding tube plasmon mode and the wire plasmon. 31,32 In this plasmon mode, same type of charges signed on both inner and outer surfaces of the outer silver tube. So the field lines inside the silver tube repel each other and result in weak electric field.…”

Enhanced optical transmission of composite subwavelength rectangular-hole array based on metal silver thin-film

“…Fano共振效应, 这也是一些异常增强透射现象产生的 原因, 在该过程中Fano共振效应将会起到透射传输和 放大的作用 [16,17] . 对于一些比较复杂的等离激元金属 微纳结构, 当亮场与暗场模式同时存在时很有可能产 生模式杂化作用 [18][19][20] . LSPs对贵金属的表面以及孔洞…”

“…其中, 国内外研究较多的课题就是如 何设计出一种复合纳米孔阵列结构从而更有效地提高 透射率, 例如, Liu等人 [26] 设计出了一种双套圆孔排列 成矩形纳米孔阵列的结构, 该结构在千兆赫兹入射光 的范围内能够获得高透射率; 以及Zhang等人 [27] [14,15] . 另外一些孔 洞中存在共振通道和非共振通道时会产生Fano共振效 应, 该效应也被用于解释一些异常透射现象, 起到了透 射传输及放大作用 [16,17] , 在一些较为复杂的等离激元 金属结构中, 当亮场与暗场模式共存时还可能产生模 式杂化作用 [18][19][20] . 对于沿y方向对称的复合矩形孔阵 参考文献…”

Unveiling ultrasharp scattering–switching signatures of layered gold–dielectric–gold nanospheres

“…where A i and B i are the constants associated with the monopole and the dipole terms, respectively [26,33]. In order to determine the potential in each region, the following boundary conditions must be satisfied at each interface [26]:…”