表面電漿效應之於金屬奈米腔體與孔穴之數值分析

本論文分為兩大主題：主題一: 奈米銀珍珠陣列及奈米銀殼珍珠對陣列之表面電漿研究利用有限元素法針對奈米銀珍珠陣列以及奈米銀殼珍珠對陣列，珍珠內部填充介電質材料研究它的表面電漿模式的效應，其模擬結果顯示奈米銀殼珍珠陣列以及奈米銀殼珍珠對陣列當中間填充介電材料時，會顯示兩個表面電漿共振模。這兩個共振模就是束縛模以及非束縛模，而這個現象是在奈米銀珍珠在同樣體積下所看不到的。主題二：奈米金屬孔穴之表面電漿研究利用有限元素法分析及計算一個三維金屬奈米孔穴之研究，經由改變孔穴半徑大小來研究它的表面電漿模式的效應，我們發現在奈米金屬孔穴周圍具有侷域性場增強現象，共振效應並不是單一奈米粒子所共振，而是由於dipole與金屬奈米孔穴周圍相互作用，使得dipole共振強度有所不同。除此之外，電荷分佈效應也在topic 2中其討論。關鍵詞：有限元素法、表面電漿、束縛模、非束縛模。

關鍵字

有限元素法；表面電漿；束縛模；非束縛模

並列摘要

This thesis is divided into two topics: In topic 1, we numerically investigate the surface plasmon resonance (SPR) modes in periodic silver-shell nanopearl and its dimer arrays with the core relative permittivities filled inside the dielectric holes (DHs) using finite element method (FEM) with three-dimensional calculations. Numerical results of resonant wavelengths corresponding to the effects of different period of unit cells, radii of DHs, illumination wavelengths and the DH core relative permittivity of silver-shell nanopearls are reported as well. Simulation results show that silver-shell nanopearl arrays and its dimer arrays with DHs exhibit tunable SPR modes corresponding to the bonding and anti-bonding modes, respectively, that are not observed for the solid silver cases with the same volume. The boundary symmetry on the inner and outer surfaces of the silver nanopearl arrays with DHs can be broken by their structural and material parameters. It is shown that only the bonding mode can be excited at the lower core relative permittivity, whereas both the bonding and anti-bonding modes can be excited at the higher core relative permittivity. In topic 2, we numerically investigate the optical properties of near field effects on an array of metallic nanohole by using finite element method. The peak resonant wavelengths can be tuned by varying the geometry of metallic nanohole size and material parameters of medium filled inside the metallic nanohole. The detail behavior of physical mechanism of surface plasmon effect in metallic nanohole are also discussed in this topic. Simulation results show that the metallic nanohole arrays with DHs exhibit red shifted phenomenon that are not observed for the air hole case. These results are crucial in designing localized SPR sensors and other optical devices based on periodic metal nanoparticle array structures. keywords: finite element method, surface plasmon resonance (SPR), bonding and anti-bonding modes.