Studies on the Fundamental Properties and Applications of Surface Plasmon Coupling with a Dipole in a Metal Surface Nano-Grating Structure

本論文中，我們利用邊界積分方程法區分在金屬表面奈米光柵結構上的侷域表面電漿子和表面電漿極化子。因為侷域表面電漿子對於幾何形狀相當敏感，而表面電漿極化子可由週期所支配，因此在製程上激發表面電漿極化子比激發侷域表面電漿子容易控制。了進一步瞭解電偶極與表面電漿子耦合的過程，我們數值模擬其暫態行為來觀察四種不同的表面電漿子模態：光柵擾動下的共振表面電漿極化子、侷域表面電漿子、光柵輔助下的表面電漿極化子以及平板界面的共振表面電漿極化子。此四種表面電漿子模態之系統衰減率包含三個主要機制：金屬損耗、往下輻射，以及沿金屬界面的能量傳輸。後，我們以數值方法探討輻射電偶極與表面電漿子耦合時，其內部量子效率以及準外部量子效率之增益。表面電漿子耦合效應可用來改善氮化銦鎵/氮化鎵量子井發光二極體綠光與紅光波段初始內部量子效率較低的情況。In this thesis, we demonstrate the differentiation between the contributions of localized surface plasmon (LSP) and surface plasmon polariton (SPP) couplings with an emitting dipole to emission enhancement in a metallic grating structure using the boundary integral-equation method (BIEM). Because the LSP resonance energy is sensitive to the metal/dielectric interface geometry, it may be difficult to control the enhancement for a desired emission wavelength based on the LSP coupling. On the other hand, because the SPP feature can be controlled by the period of a grating structure, the implementation of the SPP coupling for emission enhancement in a practical device can be more feasible.To further understand the coupling process, the transient behaviors of the dipole couplings with a grating-perturbed resonant SPP, an LSP, a grating-assisted SPP, and a flat-interface resonant SPP feature are numerically studied. The system decays of all the four SP coupling features include three major mechanisms: metal dissipation, bottom emission, and energy outward transport along the metal/dielectric interface. inally, we numerically study the enhancements of internal quantum efficiency (IQE) and quasi-external quantum efficiency (QEQE) of a radiation dipole coupled with surface plasmons. In applying the SP coupling phenomenon to an InGaN/GaN quantum-well light-emitting diode, the efficiency enhancement is more significant in the green-red range, in which the intrinsic IQE is normally quite low.Table of Contents要 IVbstract VIist of Figures Xist of Tables XIIIhapter 1 Introduction 1hapter 2 Theories 4.1 Surface Plasmon (SP) 4.1.1 Background knowledge 4.1.2 Mechanisms of surface plasmon polariton (SPP) and localized surface plasmon (LSP) 6.1.3 Quantum well (QW)-SP coupling phenomenon 9.2 Boundary Integral-Equation Method (BIEM) 11hapter 3 Differentiating LSP and SPP 17.1 The Enhancement Factors of Radiation Rate (RR) and Downward Emission (DE) 18.2 Excitation of Localized Surface Plasmon (LSP) on a Single Groove 19.3 Differentiating the Contributions between LSP and SPP on Grating Structures 21.4 Dispersion Relations of the SPs on Grating Structures 25hapter 4 Transient Study 41.1 Problem Geometry and SP-Dipole Coupling Behaviors in the Spectral Domain 42.2 Time-Resolved Behaviors of SP-Dipole Coupling 47.3 Radiative and Non-Radiative Decay Times of the Coupling System 50.4 Comparison between Grating-Perturbed Resonant SPP and Flat-Interface Resonant SPP 54.5 Evolution of the SP-Dipole Coupling Field Distribution 57hapter 5 Enhancement of Quantum Efficiencies 79.1 Definitions of Internal Quantum Efficiency (IQE) and Quasi-External Quantum Efficiency (QEQE) 79.2 Enhancement of the IQE and QEQE on a Grating Interface between Ag and GaN 81hapter 6 Conclusions 88eferences 91ublication List of Wen-Hung Chuang 9