空氣/金屬/介電質奈米光柵結構內之表面電漿子與電偶極耦合特性研究

Study on the Characteristics of Surface Plasmon Coupling with a Dipole in Air/metal/dielectric Nano-grating Structures

陳弘履(Hung-Lu Chen)

指導教授 ： 楊志忠

共同指導教授 ： 江衍偉(Yean-Woei Kiang)

國立臺灣大學/電機資訊學院/光電工程學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.02264

摘要

本論文中，我們利用邊界積分方程法來計算在空氣/銀/介電質兩種奈米光柵結構、兩種電偶極位置、頻譜範圍400至800奈米之電偶極與表面電漿子耦合產生之電偶極輻射率增益。我們區別三種表面電漿子耦合特徵，包含平面波激發之表面電漿極化子、電偶極激發之表面電漿極化子以及侷域表面電漿子。此外，我們也計算在不同電偶極位置之電偶極與表面電漿子耦合系統中的放射增益。耦合系統之放射效率決定於靠近金屬/介電質界面之場強度及相位分布。任何一種表面電漿子特性可以有效率或無效率的放射，端看金屬奈米結構、電偶極位置和頻譜位置。一般來說，當金屬銀層變薄時，主要的表面電漿極化子和侷域表面電漿子耦合特徵紅移。在耦合系統內大部分的放射能量釋放到空氣/銀/介電質奈米結構中放置電偶極側。

關鍵字

表面電漿子 ； 光柵

並列摘要

In this thesis, the dipole-surface plasmon (SP) coupling-induced dipole radiation rate enhancements over the spectral range of 400-800 nm in two air/Ag/dielectric grating nanostructures and two dipole positions based on the boundary integral-equation method are evaluated. Three kinds of SP coupling feature are identified, including plane-wave-excited surface plasmon polariton (SPP), dipole-excited SPP, and localized surface plasmon (LSP). Also, the emission enhancements of the dipole-SP coupling systems of those problem geometries on the dipole position side are calculated. The emission efficiency of a coupling system is determined by its field magnitude and phase distributions near the metal/dielectric interface. Any kind of SP coupling feature can emit either effectively or ineffectively, depending on the metal nanostructure, dipole position, and spectral location. Generally, when the Ag layer becomes thinner, the major SPP- and LSP-coupling features red-shift. The major part of emitted energy of a coupling system is released into the dipole side of the air/Ag/dielectric nanostructure.

並列關鍵字

surface plasmon ； grating

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