Surface plasmon polaritons (SPPs) mediated light extraction efficiency of light-emitting material from metallic nanohole array.

• Other Authors: Chan, Kay Fung.
• Format: Others
• Language: English; Chinese
• Published: 2012
• Subjects: Photonics; Nanostructured materials > Optical properties; Surface plasmon resonance
• Online Access: http://library.cuhk.edu.hk/record=b5549204; http://repository.lib.cuhk.edu.hk/en/item/cuhk-328751

表面等離子體激元和熒光分子之間的電磁相互作用已因廣泛應用於量子運算中的量子信息處理和分子生物技術的分子檢測而得到相當大的關注。雖然通過把熒光分子放置在電漿系統旁來改善熒光分子的發光度和方向性已被廣泛接受，但是了解表面等離子體激元和熒光材料之間的相互作用的物理亦是很重要的。 === 在這篇論文中，我們將研究在二維納米銀洞陣列上有機染料帶方向性的發光特性。通過量度在每個角度的反射和熒光發光光譜，我們可以繪製出二維納米銀洞陣列所產生的電磁共振模式的色散關係及熒光材料發光度與方向的關係。此外，在陣列上以不同方向行走的表面等離子體激元的衰變壽命亦被找出。我們亦將反射率和熒光發光光譜進行比較，從而發現熒光發光的加強跟表面等離子體激元的光譜位置、衰變後傳播的方向、它的衰變壽命和它的耦合效率有十分密切的關係。為了解背後的物理，我們建立了一個理論模型去區分能量從有機染料轉移到表面等離子體激元的過程與表面等離子體激元衰變過程對表面等離子體激元改變熒光材料發光度的影響。因此，我們可以對能量從有機染料轉移到表面等離子體激元的過程與方向的關係進行定量分析。最後，我們的研究結果與由有限差分時域模擬計算所得的結果吻合。結論得出在二維納米銀洞陣列上所實現的表面等離子體激元増加有機染料光提取效率與三維空間中方向的關係是源於電漿帶隙的產生所引致的態密度重整及分配。 === The electromagnetic interaction between surface plasmon polaritons (SPPs) and fluorescent molecules has been capturing considerable attention for a wide variety of applications ranging from quantum information processing in quantum computing to molecule detection in biotechnology. Although it is widely accepted that the light emission efficiency and directionality are improved by placing the fluorescent molecules in close proximity to a plasmonic system, the understanding of the physics on how SPPs interact with the fluorescent materials is of importance. === In this thesis, the directional emission properties of LDS organic dyes supported on two-dimensional Ag nanohole array is studied. Angle-resolved reflectivity and photoluminescence spectroscopy have been employed to map out the dispersion relations of electromagnetic resonance modes arising from the array and the dependence of plasmonic emission on emission angle. In addition, the decay lifetimes of SPP modes in different propagation directions in array have been determined. By comparing the reflectivity and photoluminescence mappings, we find that the emission enhancement is strongly correlated with the spectral and angular positions of SPP modes together with their lifetimes and coupling efficiencies. To understand the underlying physics, we have developed an analytical model to differentiate the surface plasmon mediated emission (SPME) into energy transfer from LDS to SPPs and the radiative decay of surface plasmons. As a result, the directional dependence of the energy transfer process can then be analyzed quantitatively. Finally, our results are compared with the finite-difference-time-domain simulations with good agreement. It is concluded that the directional dependence of the surface plasmon mediated emission is attributed to the redistribution of the density of states in the periodic nanohole array due to the opening of the plasmonic gaps. === Detailed summary in vernacular field only. === Detailed summary in vernacular field only. === Chan, Kay Fung = 表面等離子體激元改變納米金屬洞陣列上發光材料的光提取效率 / 陳其鋒. === Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. === Includes bibliographical references (leaves 115-123). === Abstracts also in Chinese. === Chan, Kay Fung = Biao mian deng li zi ti ji yuan gai bian na mi jin shu dong zhen lie shang fa guang cai liao de guang ti qu xiao lu / Chen Qifeng. === Chapter Chapter 1 --- Introduction --- p.1 === Chapter 1.1 --- Surface plasmon polaritons (SPPs) and surface plasmon mediated emission (SPME) --- p.2 === Chapter 1.2 --- Directional surface plasmon mediated emission (SPME) on metallic nanohole array --- p.5 === Chapter 1.3 --- Our analytical model of surface plasmon mediated emission --- p.8 === Chapter 1.3.1 --- Formalism of rate equations --- p.8 === Chapter 1.3.2 --- Determination of the directional dependence of the coupling efficiency from decay rates of the SPP and the fluorescent material --- p.11 === Chapter 1.4 --- Organization of the thesis --- p.12 === Chapter Chapter 2 --- Theory of surface plasmon polaritons --- p.14 === Chapter 2.1 --- The Maxwell’s equations and the boundary conditions for electromagnetic waves --- p.14 === Chapter 2.2 --- Dielectric constant of metal --- p.18 === Chapter 2.3 --- Master equation for electromagnetic waves, the Bloch form of SPPs and the dispersion relation of SPPs at the interface between dielectric and metal --- p.19 === Chapter 2.4 --- Excitation of surface plasmon polaritons by grating coupling --- p.27 === Chapter 2.5 --- Decay of surface plasmon polaritons --- p.29 === Chapter 2.5.1 --- Non-radiative decay --- p.29 === Chapter 2.5.2 --- Radiative decay --- p.31 === Chapter Chapter 3 --- Experimentation and Simulation --- p.37 === Chapter 3.1 --- Sample preparation --- p.37 === Chapter 3.1.1 --- Interference lithography [2.2, 3.7, 3.8] --- p.37 === Chapter 3.1.2 --- E-beam evaporation --- p.39 === Chapter 3.1.3 --- Spin coating of florescence material --- p.40 === Chapter 3.2 --- Measurements --- p.41 === Chapter 3.2.1 --- Angle-resolved specular reflection measurement [3.10] --- p.42 === Chapter 3.2.2 --- Angle-resolved photoluminescence (PL) spectroscopy [3.11] --- p.43 === Chapter 3.2.3 --- K-space (Fourier space) imaging [3.12, 3.13, 3.14] --- p.44 === Chapter 3.3 --- FDTD --- p.46 === Chapter 3.3.1 --- Theory of FDTD --- p.46 === Chapter 3.3.2 --- Simulation of the reflectivity of plane wave --- p.52 === Chapter 3.3.3 --- Simulation of the field pattern with a dipole source --- p.55 === Chapter 3.3.3.1 --- Near-to-far field projection --- p.59 === Chapter 3.3.3.2 --- Near field pattern in k-space --- p.60 === Chapter Chapter 4 --- Analysis --- p.62 === Chapter 4.1 --- Angle-resolved reflectivity measurement --- p.62 === Chapter 4.1.1 --- SPP mode identification --- p.62 === Chapter 4.1.2 --- Wavelength dependence of uncoupled SPPs decay rates --- p.65 === Chapter 4.1.3 --- Directional dependence of uncoupled SPPs decay rates --- p.71 === Chapter 4.2 --- Angle-resolved PL spectroscopy --- p.79 === Chapter 4.2.1 --- Comparison with the angle-resolved reflectivity --- p.79 === Chapter 4.2.2 --- Differentiation of the resonance and off-resonance positions on the PL mapping --- p.81 === Chapter 4.3 --- K-space imaging --- p.83 === Chapter 4.3.1 --- Reflectivity and the comparison with the phase - matching equation --- p.83 === Chapter 4.3.2 --- k-space imaging of the PL emission --- p.85 === Chapter 4.4 --- Directional dependence of the emission factor --- p.86 === Chapter 4.5 --- Directional dependence of the coupling rate of the LDS emission to the SPP mode --- p.94 === Chapter 4.6 --- Near field in k-space from the FDTD method --- p.97 === Chapter Chapter 5 --- Conclusions --- p.113 === Bibliography --- p.115