The Modulation Effect of Photoluminescence of Plasmonic Nanoantennas

電漿奈米結構之螢光發光的調頻效應

黃振咸(Chen-Hsien Huang)

指導教授 ： 黃哲勳

國立清華大學/理學院/化學系/碩士(2015年)

摘要

本論文中探討不同尺寸的金奈米天線之螢光放光行為，試圖控制其螢光放光之頻率。因為金奈米天線的表面電漿共振模態可以塑造其螢光的放光頻率，而藉由調整金奈米天線的構型，可以改變其表面電漿共振之頻率，從而導致不同的螢光放光光譜。在本論文中，我們製作出不同尺寸及大小的金奈米天線，觀察不同尺寸之單一金奈米柱以及對稱金奈米天線的螢光放光性質，了解金奈米結構之螢光放光頻率與其表面電漿共振模態之間的關係。在對稱金奈米天線的螢光光譜中，我們看到其Fundamental mode、antibonding mode與higher-order mode在螢光光譜上的呈現，且會隨著金奈米天線尺寸的漸增而調整其螢光放光光譜的位置，此光譜趨勢與散射光譜與模擬光譜的趨勢相符合，但與呈現表面電漿共振頻率的散射光譜相比，卻有一明顯的藍位移，而此現象並不會發生在單一的金奈米柱上。本論文之研究可使我們對金奈米結構的發光性質有更深入的了解，並希望在未來能夠清楚其發光機制。

關鍵字

奈米天線 ； 表面電漿共振 ； 螢光放光

並列摘要

A gold plasmonic nanoantenna can provide additional local density of optical states (LDOS) for excited quantum emitters to radiative decay and thereby can shape the emission properties of the emitters. One example is the modulation of the antenna’s photoluminescence spectrum. Here, we fabricate gold nanoantennas with various size and study the modulation effect of gold nanoantennas systematically. All of the symmetry antennas show obvious modulation effects on the photoluminescence spectrum due to the transverse resonance, antibonding, higher-order and fundamental longitudinal localized surface plasmon resonance mode. The spectral features are in good agreement with that in the spectra obtained from dark-field scattering and numerical simulations. However, we have repeatedly observed extraordinary blue spectral shift for resonant modes between scattering and photoluminescence spectrum in symmetry antenna, but can’t observe in single nanorod. Our work shows that photoluminescence is strongly modulated by the LDOS of the nanoantennas and therefore can be used as a local luminescence source to report the LDOS.

並列關鍵字

Nanoantenna ； Plasmonic resonance ； Photoluminescence

參考文獻

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