本論文主要探討殼核奈米金屬柱之表面電漿共振模態，並以混成模型理論(Hybridization model)來解釋之。將原本之單一奈米金屬球製做成殼核結構後，其光學響應會和原先之單一粒子有所不同，產生如吸收頻譜的增強，共振波長的紅移、藍移等現象。在分析上我們將複雜奈米金屬結構分割成許多較為簡單之基本形狀，並逐一探討不同模態的電漿子能量高低，最後再探討各個基本結構之模態耦合結果。
　　首先由最基本的單一奈米金屬結構開始，使用有限差分時域法(Finite-Difference-Time-domain method, FDTD Method)模擬金/銀材質比對奈米金屬球之影響、奈米球與奈米柱之差異，最後探討將奈米柱加上一層金屬外殼後之殼核奈米金屬柱結構。為了瞭解殼核奈米金屬柱之模態組成，我們將之分成中心柱狀部分、外殼以及在其間的間隙來探討，逐一釐清所具有的共振模態及原理。
　　最後我們成功地運用混成模型理論將奈米柱、外殼以及間隙所具有之模態耦合成殼核奈米結構下所具有之模態，並且解釋了各種不同模態間之電漿子能量高低。以上之研究與討論也為將來設計殼核奈米粒子產生共振效果帶來新的觀點及研究方向。

Recently, a new type of plasmonic metallic rod-in-shell nanostructure has been reported, which has greater localized surface plasmon resonant (LSPR) strength than Au NRs. However, the optical property of a single rod-in-shell nanoparticle is rarely been studied. Here, we use Finite-Difference Time-Domain (FDTD) method to study the plasmonic resonance mode of rod-in-shell structure and use the hybridization model to understand the physical mechanism. In our analysis, the structure of Au NR-in-Au-shell is divided it into three basic elements, Au NR, Au shell and the gap between rod and shell, and investigated separately. The resonant mode of Au NR-in-Au shell can be traced back to the energy level of plasmon resonant mode of each basic element. The effect of shell thickness and gap size lead to different surface plasmon coupling strength and different overall structure aspect ratio which all contribute to the spectra shift. Subsequently, we used hybridization theory to explain the energy level of Au NR-in-Au shell. The result shown in this thesis could provide a new perspective on the design of resonant mode of rod-in-shell nanostructures for bio-medical applications.

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