Radiative decay and coupling of surface plasmons on metallic nanohole arrays.

• Other Authors: Lo, Hau Yung.
• Format: Others
• Language: English; Chinese
• Published: 2013
• Subjects: Plasmons (Physics); Metallic composites; Nanostructures > Optical properties; Surface plasmon resonance
• Online Access: http://library.cuhk.edu.hk/record=b5549308; http://repository.lib.cuhk.edu.hk/en/item/cuhk-328563

了解表面等子體和外部環境之間的相互作用對表面等子體應用的開發非常重要。我們的研究集中在表面等子體與遠場的耦合，以及表面等子體模之間的耦合。 === 首先，我們研究由表面等子體模式耦合所產生的射衰變的變化。我們以角分辨反射光譜測同孔大小的納米孔陣上的簡併表面等子體模的衰減。對於每個孔的大小，我們觀察到在發生共振耦合的光譜區，衰減速有很大的改變，顯示出暗模和模的形成。耦合模很好地解釋衰變的變化。推導出的耦合常隨著孔直徑的增加而增加。我們也對耦合模一些有趣的特性及衰減變化的微觀起源進探討。 === 第二，我們以偏振分辨反射光譜從二維屬陣射散射。我們發現，反射光譜遵循的法模型可以由耦合模和瓊斯矩陣演算推導出。通過用正交方向的偏光器和分析器，反射光譜上的谷翻轉成峰，從以能夠測定出射散射效。我們發現，射散射效與波長和孔直徑的依賴關係和單孔的瑞散射相符合。 === 最後，我們開發一個新的方法，以偏振分辨光譜在實驗中測射衰變。這方法的有效性通過時域有限差分計算得到證明。我們還將此方法應用在實驗據上作為示範。 === Understanding the interaction between surface plasmon and outer environment is crucial in development of plasmonic applications. Our study is focused on the coupling between surface plasmons and far field, and also the coupling between surface plasmon modes. === First, we studied the change in radiative decay rate due to coupling of degenerate surface plasmon modes. We measured the decay rates of two degenerate surface plasmon modes in Au nanohole arrays with different hole sizes by angle-resolved reflectivity spectroscopy. For each hole size, at the spectral region where resonant coupling occurs, we observed a large modification in decay rates, leading to the formation of dark and bright modes. The change in decay rates is well explained by coupled-mode theory. The deduced coupling constant is found to increase with increasing hole diameter. Interesting properties of the coupled modes and microscopic origin of the change in decay rate is also discussed. === Second, we measured the radiative scattering from two-dimensional metallic arrays by using polarization-resolved reflectivity spectroscopy. We found that the reflectivity spectra follow the Fano-like model which can be derived from coupled-mode theory and Jones matrix calculus. By orthogonally orienting the incident polarizer and the detection analyzer, reflectivity dips flip into peaks and the radiative scattering efficiency can be determined accordingly. The dependence of total radiative scattering efficiency on wavelength and hole diameter is found to agree well with Rayleigh scattering by single hole. === Finally, we developed a new method to measure radiative decay rates experimentally by polarization-resolved reflectivity spectroscopy. The validity of this method is proved by finite-difference time-domain simulation. We also applied this method on experimental data as a demonstration. === Detailed summary in vernacular field only. === Detailed summary in vernacular field only. === Detailed summary in vernacular field only. === Detailed summary in vernacular field only. === Lo, Hau Yung = 表面等離子體在金屬納米孔陣列的輻射衰減及耦合 / 羅孝勇. === "December 2012." === Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. === Includes bibliographical references (leaves 88-92). === Abstracts also in Chinese. === Lo, Hau Yung = Biao mian deng li zi ti zai jin shu na mi kong zhen lie de fu she shuai jian ji ou he / Luo Xiaoyong. === Chapter 1 --- Introduction --- p.1 === Chapter 2 --- Basic Theory and Techniques --- p.3 === Chapter 2.1 --- Macroscopic Maxwell Equations and Boundary Conditions --- p.3 === Chapter 2.2 --- Symmetries and Band Structure --- p.4 === Chapter 2.3 --- Coupled-mode Theory --- p.10 === Chapter 2.4 --- Finite-difference Time-domain Simulation --- p.12 === Chapter 2.5 --- Preparation of Metallic Nano-hole Arrays --- p.14 === Chapter 3 --- Fundamentals of Surface Plasmons on Metallic Nanohole Array --- p.18 === Chapter 3.1 --- Confinement and Propagation Nature of SPs --- p.18 === Chapter 3.2 --- Skin Depth and Propagation Length --- p.19 === Chapter 3.3 --- Dispersion Relation and Phase-matching Conditions --- p.21 === Chapter 3.4 --- Measurement of Band Structure: Angle-resolved Reflectivity Mapping --- p.23 === Chapter 3.5 --- Red Shift of Band Structure --- p.26 === Chapter 3.6 --- Comparison of Two Presentations of Band Structure: "ω against k" versus "λ against θ" --- p.28 === Chapter 3.7 --- Resonance Peak Shape: FanoModel and Wood's Anomalus --- p.30 === Chapter 3.8 --- Resonance Peak Shape: "Fano-like" Model --- p.34 === Chapter 3.9 --- Appendix A: Derivation of Eq(3.1) --- p.36 === Chapter 4 --- Decay Rates Modification though Coupling of Degenerate Surface Plasmon modes --- p.40 === Chapter 4.1 --- Introduction --- p.40 === Chapter 4.2 --- Measurements of Degenerate Surface Plasmon Modes --- p.42 === Chapter 4.3 --- Decay rates of Coupled Modes --- p.45 === Chapter 4.4 --- Hole Diameter Dependence of Coupling Constants --- p.47 === Chapter 4.5 --- Understanding the S-polarized Surface Plasmon Modes --- p.50 === Chapter 4.6 --- TE-like Surface Plasmon Modes --- p.53 === Chapter 4.7 --- Microscopic Origin of the Modification in Decay Rate --- p.54 === Chapter 4.8 --- Summary --- p.60 === Chapter 5 --- Direct Measurement of Radiative Scattering of Surface Plasmon Resonance from Metallic Arrays by Polarization-resolved Reflectivity Spectroscopy --- p.61 === Chapter 5.1 --- Introduction --- p.61 === Chapter 5.2 --- Theory of Direct Measurement of Radiative Scattering --- p.62 === Chapter 5.3 --- Comparison with Experiment --- p.65 === Chapter 5.4 --- Comparison with Rayleigh Scattering Model --- p.71 === Chapter 5.5 --- Summary --- p.74 === Chapter 6 --- A Method of Obtaining Radiative Decay Rates From Experiment --- p.76 === Chapter 6.1 --- Introduction --- p.76 === Chapter 6.2 --- Method --- p.77 === Chapter 6.3 --- Prove of Validity --- p.78 === Chapter 6.4 --- Experimental Demonstration --- p.82 === Chapter 6.5 --- Summary --- p.85 === Chapter 7 --- Conclusion --- p.86 === Chapter 8 --- Bibliography --- p.88 === Chapter 9 --- Curriculum Vitae --- p.93