銀奈米結構之電漿子共振模態對螢光共振能量轉移的影響

Abstract

本研究探討銀奈米殼、銀奈米桿等結構的電漿子共振模態所產生的各種光學特性。分析銀奈米結構之電漿子共振模態對於兩個螢光分子的螢光共振能量轉移(fluorescence resonance energy transfer, FRET)之能量轉移效率的影響，以及對螢光分子的螢光增強效益的影響。根據Maxwell電磁理論，我們分別以Mie理論以及並矢格林函數等解析解，分析單顆球型銀奈米殼受到不同頻率的平面波或電偶極波源作用下內外域的電磁場分佈，探討各個電漿子共振模態的近、遠場特性及對螢光共振能量轉移的影響。並且使用多重多極展開法計算複雜結構，討論銀奈米桿或雙顆銀奈米殼的電漿子共振特性，對分子的螢光增益及螢光共振能量轉移的影響。 計算結果顯示銀奈米殼或銀奈米桿結構透過特定的入射方向及電場極化方向可以激發於特定區域內的螢光分子，一旦螢光分子受到激發，其能量的轉移會與電漿子共振模態和量子效應有關。特別是對於銀奈米桿，在固定細長比的情況下，銀奈米桿的兩端愈尖者，愈能提供較強的能量轉移效率。 在雙顆銀奈米殼的研究中發現，相較於單顆銀奈米殼，雙顆銀奈米殼的耦合效應對於位於間隙中的螢光分子具有更大的螢光增強效應，且其第一個模態有著明顯的紅位移。

In this thesis, we studied the interactions among fluorescent molecules, silver nanoshell (SNSs), and silver nanorods (SNRs). Analysis the surface plasmon resonance modes of silver nanostructures for fluorescence resonance energy transfer(FRET) of energy transfer rate of two fluorescent molecule, and enhancement factor of the fluorescent molecule.Based on Maxwell's equations, we obtained the the analytical solutions internal and external electromagnetic field in the metal ball nanoparticles by plane wave incident or electric dipole source analytic solution to explore various modes of electromagnetic fields near the nature of the far-fielduse of dyadic Green's function , Mie theory, and. the multiple-multipole (MMP) method was used to solve these problems, We studied the surface plasmon resonances (SPRs) of these nanoparticles irradiated by different incident plane waves with different polarizations. The calculation results show that silver nanoshell structure can be excited through a specific incidence direction and the electric polarization of fluorescent molecules within a specific area, and once the fluorescent molecules are excited, the energy transfer with the resonant modes of the scattering body and quantum effects are closely related. The silver rods scatter, the longer longitudinal axis c, said silver nanorods more sharp, can provide a stronger radiation and non-radiation efficiency and energy transfer rate. In research of the silver nanoshells enhancement factor found that the efficiency of silver nanoshell dimer more strong than single,and first mode has obvious red shift.