陣列式金屬奈米粒子表面電漿子研究

Abstract

根據Maxwell電磁理論，探討無限域中陣列式金屬奈米粒子受到磁場在z軸方向極化之高斯電磁波所造成之表面電漿子現象。多重中心展開法為主要架構之理論，使用多個展開中心展開散射體之散射場與內域場，在散射體之邊界上取點並滿足邊界條件，配合奇異值拆解法求得係數以計算電、磁場。 本研究主要為陣列式金屬奈米粒子之能量傳遞情形之探討，多顆銀奈米粒子排列為各式奈米粒子結構，如單排奈米粒子陣列結構、雙排奈米粒子陣列結構、轉向奈米粒子陣列結構、Y型奈米粒子陣列結構、六角形奈米粒子陣列結構之能量傳遞研究。由研究結果發現調整銀奈米粒子之粒徑，可造成能量傳遞發生紅移與藍移之現象，並且粒子之間距存在最佳間距之參數。並發現能量無法傳遞於各式轉向奈米粒子陣列結構末端，六角形奈米粒子陣列結構能量傳遞情形為低頻率可使能量進入結構之現象。

Surface Plasmon resonances of silver nanoparticle array under the Gaussian beam are investigated. By using Maxwell’s equation and mutli-multipole method, a set of linear equations of expansion coefficients is first constructed by satisfying boundary condition pointwisely. Singular value decomposition is then used to solve the overdetermined linear equation. Numerical results of sliver nanoparticle array under the Gaussian beam with energy transmission are presented. The single nanoparticle array, double nanoparticle array, Y-shape nanoparticle array and hexagonal nanoparticle array are discussed. It is demonstrated from numerical result that the energy transmission are depend on radius and gap of particles, and different particle radius lead to bandwidth red-shift. Energy fails to propagate to the end of nanoparticle turned structure, and low frequency pass filter appears in both case of hexagonal structure.