Abstract Optical responses in dilute composites are controlled through the local dielectric resonance of metallic clusters. We consider two located metallic clusters close to each other with admittances $\varepsilon$1 and $\varepsilon$2. Through varying the difference admittance ratio $\eta [ = (\varepsilon _2 - \varepsilon_0 ) / (\varepsilon _1 - \varepsilon _0 )]$, we find that their optical responses are determined by the local resonance. There is a blueshift of absorption peaks with the increase of $\eta$. Simultaneously, it is known that the absorption peaks will be redshifted by enlarging the cluster size. By adjusting the nano-metallic cluster geometry, size and admittances, we can control the positions and intensities of absorption peaks effectively. We have also deduced the effective linear optical responses of three-component composites $\varepsilon _{\rm e} = \varepsilon _0\bigl(1 + \sum_{n = 1}^{n_{\rm s} } [({{\gamma _{n_1 } + \eta \gamma_{n_2 } })/({\varepsilon _0 (s - s_{n} )})]} \bigr)$, and the sum rule of cross sections: $\sum_{n = 1}^{n_{\rm s} } {(\gamma _{n_1 } +\eta \gamma _{n_2 } ) = N_{h_1 } + N_{h_2 } } $, where $N_{h_1}$ and $N_{h_2}$ are the numbers of $\varepsilon _1 $ and $\varepsilon _2$ bonds along the electric field, respectively. These results may be beneficial to the study of surface plasmon resonances on a nanometre scale.
Received: 02 June 2006
Revised: 02 August 2006
Accepted manuscript online:
PACS:
61.46.Bc
(Structure of clusters (e.g., metcars; not fragments of crystals; free or loosely aggregated or loosely attached to a substrate))
(Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures)
Fund: Project supported by the
National Natural Science Foundation of China(Grant Nos 10304001,
10334010, 10521002, 10434020, 10328407 and 90501007).
Cite this article:
Chen Liang-Liang(陈亮亮), Gu Ying(古英), Wang Li-Jin(王立金), and Gong Qi-Huang(龚旗煌) Controlling optical responses through local dielectric resonance in nanometre metallic clusters 2007 Chinese Physics 16 249
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