表面等離子共振 (SPR) 是受激發的電子的總體振動，一般在金屬、電介質界面上發生。我們能以振盪的電場去激發SPR。由於表面等離子共振時會產生巨大的增強電場，這令他在近場光學與納米光學中有著廣泛的應用。例如：微流控芯片、等離子波導、隱形裝置等等。 / 在這論文中，我們會研究納米金屬體之間的作用力。基於以下原因，這在納米技術中是一個重要課題。第一，當了解到物體之間的作用力後，我們可以以此開發出把納米尺寸的物體移動與放置的方法，有助於用自下而上式的方法製作納米器件。第二，物體之間的作用力會改變器件中納米顆粒的位置，因而會影響器件的特性。 / 在一般情況下，納米尺寸的物體的作用力都可以略去不理的，因為作用力是與體積成正比。但是，當表面等離子共振發生時，相互作用力會急速地增強。這增強是由於金屬顆粒的電偶會急速地增強的原故。我們稱這現象為「表面等離子共振增強光泳」 (SPREP). / 這論文由三個主要部份組成。第一部份，我們研究一帶梯度的金屬納米球與一振盪及旋進電偶之間的相互作用。我們以第一原理進路去解決這問題，並作了長波長假設。我們的解析解能夠處理多極效應，這效應在外場不均勻時是不可忽略的。我們探討了作用力、力矩、電場分佈。更發現了，當金屬納米球的梯度很高時，電偶與金屬納米球之間與有一穩定的力平衡。這研究有助於開發新型的光學鑷子。 / 第二部份，我們探討兩個金屬納米球之間的 SPREP，我們介紹了不同的計算方法。Bergman-Milton譜表示以及多重鏡象法。 兩個金屬納米球之間也有著穩定的平衡， 這表示在一群納米球中，可能有著穩定結構。這穩定的平衡，是由於表面等離子共振的頻率與相互距離有關，這是一種多體效應。這研究有助於了解納米簇的結構形成。 / 最後，我們以離散偶極子近似法(DDA)研究多體問題，雖然DDA並不是精確解，但當顆粒之間相距不太接近時，這依然是一個良好的近似。當顆粒的數量太多時，我們以等效介質理論去著手，不再考慮每一顆粒各自的位置，而只考慮顆粒的濃度。 / Surface plasmon resonance (SPR) is the collective electrons excitations, which occurred at the metal-dielectric interfaces and can be induced by an oscillating electric field. Because of the large field enhancement, SPR has a wide range of applications in near field optics and nano-optics, such as biosensors, lab-ona- chip devices, plasmonic waveguides, and cloaking devices. / In this thesis, we study the interparticle forces between metallic nanosized objects. It is an important topic in nanotechnology for at least two reasons. Firstly, the study of the interparticle forces may provide methods to control the motion and position of nano-size objects, which can be used to fabricate artificial nano-structure by bottom up approach. Secondly, the force can change the arrangement of the particles in the nanodevices and hence affecting the property of the devices. / The interparticle forces of nano-sized dielectric particles are negligible, since the force is proportional to the volume of the objects. However, the interparticle forces of metallic particles will be greatly enhanced when SPR occurs, which is able to compensate the volume effect. This phenomenon is called surface plasmon resonance enhanced photophoresis (SPREP), which is one of the consequences of the rapid increase in the dipole moment in the particles. / This thesis is consisted of three main parts. In the first part, we study the SPREP between a graded metallic nanosphere and a point dipole which is undergo oscillation and precession. A first principle approach is applied to handle this problem. Our analytic solutions are able to capture the multipole effect, which cannot be neglected in highly non-uniform fields. We have analyzed three important physical quantities: the induced force, the induced torque, and the field distribution. Furthermore, we find that there is a binding between the nanoparticle and the dipole source, when the gradation of the graded particles is large enough. This study has a potential application in developing a novel kind optical tweezers. / In the second part, we study the SPREP between two metallic nanoparticles. The force spectra are calculated by two different methods: Bergman- Milton spectral representation and multiple image method. The binding between two nanoparticles is observed, which indicates a possible stable structure among the metallic clusters. The binding is caused by the excitation of collective plasmon modes, and the consequence that the resonance poles sℓ are the functions of separation distances. This study may provide a better understanding in the structure formation of colloidal clusters in nano-scales. / Finally, we consider a many-particle system by the discrete dipole approximation (DDA) and effective medium theory. Although, the DDA is not an exact formalism, it is a suitable approximation for considering finite number of particles, if the distances among particles are not too close. When the number of particles in the host solution is large, we can use the effective medium theory to handle the problem. Instead of considering all discrete particles individually, we will consider the interaction between a single particle and a new effective host solution, where the dielectric function of the effective host solution is determined by the concentration of nanoparticles in the host solution. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Chan, Kin Lok = 納米金屬顆粒中的表面等離子共振增強光泳 / 陳建樂. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 90-94). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Chan, Kin Lok = Na mi jin shu ke li zhong de biao mian deng li zi gong zhen zeng qiang guang yong / Chen Jianle. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Nanoparticles and nanotechnology --- p.1 / Chapter 1.2 --- The history of nanoparticles and nano-optics --- p.1 / Chapter 1.3 --- Applications of nanoparticles --- p.2 / Chapter 1.3.1 --- Optical applications --- p.2 / Chapter 1.3.2 --- Biological and medical applications --- p.3 / Chapter 1.4 --- Electrokinetics of nanoparticles --- p.4 / Chapter 1.4.1 --- Review on recent work on electrokinetics --- p.5 / Chapter 1.5 --- Objectives of the thesis --- p.6 / Chapter 2 --- Basic Principles --- p.8 / Chapter 2.1 --- Drude model --- p.8 / Chapter 2.2 --- Complex dielectric function --- p.9 / Chapter 2.2.1 --- Electric field in an imperfect conductor --- p.10 / Chapter 2.3 --- Effective medium theory --- p.11 / Chapter 2.3.1 --- Maxwell-Garnett approximation --- p.12 / Chapter 2.3.2 --- Bruggeman approximation --- p.13 / Chapter 2.3.3 --- Bergman-Milton spectral representation (BMSR) --- p.13 / Chapter 2.3.4 --- Effective dielectric function of shelled sphere --- p.17 / Chapter 2.4 --- Surface plasmon resonance (SPR) --- p.18 / Chapter 2.5 --- Surface plasmon resonance enhanced photophoresis (SPREP) --- p.20 / Chapter 2.6 --- Justification of long wavelength limit --- p.23 / Chapter 3 --- Manipulation of Nanoparticles by a Single Dipole Source --- p.25 / Chapter 3.1 --- Introduction --- p.25 / Chapter 3.2 --- Formalism --- p.26 / Chapter 3.2.1 --- Electrostatic potential of a dipole --- p.27 / Chapter 3.2.2 --- Electrostatic potential of a dipole in terms of multipole expansion --- p.27 / Chapter 3.2.3 --- Laplace's equation of graded sphere --- p.30 / Chapter 3.2.4 --- Boundary value problem --- p.31 / Chapter 3.2.5 --- Force --- p.33 / Chapter 3.2.6 --- Torque --- p.35 / Chapter 3.3 --- Result and discussion --- p.36 / Chapter 3.3.1 --- Force --- p.38 / Chapter 3.3.2 --- Torque --- p.45 / Chapter 3.3.3 --- Electric field distribution --- p.46 / Chapter 3.4 --- Conclusion --- p.48 / Chapter 4 --- Interaction between Two Objects --- p.49 / Chapter 4.1 --- Introduction --- p.49 / Chapter 4.2 --- Interaction between two particles --- p.50 / Chapter 4.2.1 --- Dipole approximation --- p.50 / Chapter 4.2.2 --- Multiple images method --- p.52 / Chapter 4.2.3 --- Bergman-Milton spectral representation for collection of grains --- p.58 / Chapter 4.2.4 --- Equation of motion --- p.61 / Chapter 4.2.5 --- Result and discussion --- p.62 / Chapter 4.3 --- Particle near a conducting plane --- p.67 / Chapter 4.3.1 --- Dipole approximation --- p.67 / Chapter 4.3.2 --- Multiple image method --- p.69 / Chapter 4.3.3 --- Result and discussion --- p.70 / Chapter 5 --- Many-particle Systems --- p.72 / Chapter 5.1 --- Introduction --- p.72 / Chapter 5.2 --- Discrete dipole approximation --- p.72 / Chapter 5.2.1 --- 2-particle system --- p.73 / Chapter 5.2.2 --- 4-particle system --- p.74 / Chapter 5.2.3 --- Result and discussion --- p.75 / Chapter 6 --- Concentration Effect --- p.80 / Chapter 6.1 --- Introduction --- p.80 / Chapter 6.2 --- Formalism --- p.81 / Chapter 6.2.1 --- Result and discussion --- p.83 / Chapter 7 --- Summary --- p.88 / Bibliography --- p.90 / Chapter A --- Eigenfunctions, Eigenvalues, and Green's function --- p.95 / Chapter A.1 --- Isolated sphere --- p.95 / Chapter A.1.1 --- Eigenfunctions and eigenvalues --- p.96 / Chapter A.1.2 --- Green's function --- p.98 / Chapter A.2 --- Planar interface --- p.98 / Chapter A.2.1 --- Eigenfunctions and eigenvalues --- p.99 / Chapter A.2.2 --- Green's function --- p.100 / Chapter B --- Property of Spherical Harmonics and Associated Legendre Polynomials --- p.101 / Chapter B.1 --- Complex conjugate of Yℓm(Ω): --- p.102 / Chapter B.2 --- Differential Property --- p.102 / Chapter B.3 --- Limiting value --- p.102

基於表面等離子體的納米器件已經在近幾十年引起了十分廣泛的興趣因為其對於半波長光子器件，光學傳感，光譜學以及光學捕獲有著廣大的應用前景。表面等離子體是一種被限定於金屬和介質介面上的一種光子-電子混合模式，而且它具有許多吸引人的特質，比如對金屬表面周圍環境極其敏感，納米尺度範圍的光學電磁場局域和場增強，以及對鄰近物體極強的場強梯度捕獲力。雖然這些特性都已經分別被廣泛的研究過，但從光學捕獲的角度去實現光學傳感的方案並還沒有引起大量的關注。很明顯，在納米尺度範圍內操縱目標的可能性將使得新的納米器件具有高的光學探測性能和多功能性。為了涉及這個論題，本項目包括新穎的等離子體納米器件的研究，這些納米器件將能夠提供獨特的功能，在光學傳感，表面增強拉曼散射，以及光學捕獲方面。 / 在第一部分設計中，構建了一種基於雙層金屬納米條陣列的耦合系統。這樣的系統具有簡單的結構，易於加工和集成於微流系統的優點。由於這個系統內的光場耦合，場強可以進一步的被加強，這樣的特點有助於提高系統的敏感特性，尤其是通過強的光場來捕獲一些金屬的納米顆粒後。這個系統的光學共振條件可以從理論上進行模式分析得到。然後二維時域有限差分法證實了理論的分析而且進一步證明了利用該系統於光學傳感和捕獲的可能性。結果表明此系統的光學敏感度約為200nm/RIU，通過光學捕獲的金屬納米顆粒引起的近場調製和場增強可以使得表面增強拉曼散射的增強因數達到10⁹ 到10¹° 的高度。 / 在第二部分的設計裡，金納米環結構被證實了可以成為一個強大的工具作為表面等離子體納米光鑷來抓獲金屬納米顆粒。首先，金屬納米環具有很多優點比如對入射光的偏振不敏感，很寬的可調的共振範圍，有環的內腔周圍和內部有著均勻的光學場增強，以及很容易製備。這裡的設計著重于納米環在入射波長為785nm 的新穎的光學捕獲特性以及表面增強拉曼散射的性能。三維的時域有限差分法被用來計算結構的光學回應，以及麥克斯韋應力張量法被用來計算光學受力分佈情況。計算結果表明對於一個有20nm 大小的金納米顆粒球，納米環結構有最大的光學捕獲勢阱約32 KgT 。由於納米環結構周圍存在多個捕獲勢阱，使得其對目標捕獲顆粒具有約10⁶nm³ 的非常之大的有效體積。而且，被捕獲的顆粒會進一步的導致一些納米間隙的形成，這些納米間隙又會使得近場增強達到約160 倍的高度，這使得在實際應用中10⁸ 的表面增強拉曼散射的增強因數成為可能。 / 在第三部分的設計裡，全光納米操縱的概念被提出並證實，因為這樣的概念拓展了等離子體光鑷的一個極其重要的功能，那就是被捕獲的分子可以在捕獲和區域內被任意的操縱和轉移，而且這個區域是納米尺度的。設計的系統由梯度形金屬納米盤組成，這些納米盤具有不同的直徑，這使得它們支援不同波長的表面等離子體共振。通過改變入射光的波長和旋轉入射光的偏振態，就可以將捕獲的目標從一個納米盤轉移到另一個納米盤。三維的時域有限差分法和麥克斯韋應力張量法被用來證實了所提出的觀點。計算結果表明被捕獲的目標感受到的捕獲勢阱深度高達5000kgT/W/μm²，最大的光學轉矩約為336pN·nm/W/μm²，而且總的有效捕獲體積可達到10⁶nm³ 。在這部分的結尾，討論了所設計的系統在光學傳感方面潛在的應用前景。 / 在最後的部分裡，展示了一個實驗的證明來說明等離子體納米光鑷對目標捕獲的觀測問題，因為這樣的觀測對往後近期的相關實驗來說是首先要關心的問題。雖然兩種途徑已經在別處被證實了，分別是通過觀測系統的透射光的強度變化和系統共振波長的改變，來監測表面等離子體納米光鑷近場捕獲行為的發生，但是在這個部分裡，等離子體納米光鑷和表面增強拉曼傳感技術被結合在了一起並且被證實了這是另一種有效的方法用於觀測捕獲行為的發生。在本實驗中兩束鐳射光束被為別用來激發等離子體納米光鑷和表面增強拉曼信號，一束是633nm 的鐳射，另一束是785nm 的鐳射。表面等離子體納米光鑷簡單地由熱蒸鍍並熱退光的金顆粒納米島墊底構成，這個墊底的共振峰被調製到緊靠633nm 的位置。目標顆粒是由光化學生長合成的銀納米十面體，這些十面體被綁定了4-巰基苯甲酸分子的單分子層，且具有遠離633nm 和785nm 的共振峰。由於當等離子體納米光鑷被激勵的時候目標顆粒會被捕獲到近場的熱點內，這時近場的光場就會被極大的增強，所以表面增強拉曼的信號就會出現。這個過程也被用數值模擬的方法（三維時域有限差分法和麥克斯韋應力張量法）闡明了。更進一步的，當等離子體納米光鑷不被激勵的時候，被捕獲的目標顆粒可以被釋放掉，那樣表面增強拉曼的信號就會消失掉。所以，本設計不僅提供了一種強有力的探測等離子體光鑷捕獲行為的方法，而且能夠成為一種在生物探測方面可重複利用的“捕獲并傳感“的平臺。 / Surface plasmons (SPs) based nanodevices have attracted much research interest in recent decades due to their powerful application potentials for subwavelength optical circuits, optical sensing, spectroscopy, and optical trapping. SPs are the hybrid photon-electron modes bound at the interface of conductors and transparent materials, and they have lots of attractive properties such as sensitive to the changes of environment around the interface, strong optical field localization and enhancement in nanoscale domain, and strong field intensity gradient forces to trap the adjacent objects. Even though these properties have been widely investigated, their application in optical sensing based on the plasmonic optical trapping strategy remains largely unexplored. Clearly, the possibility of manipulating objects within the nanometer regime will enable new nanodevices that offer high optical detection performance and multiple-functionality. With the aim to address this issue, this project involves the study of novel plasmonic nanodevices that provide unique functionality in optical sensing, surface-enhanced Raman scattering (SERS), and optical trapping. / The first design is based on a coupling system involving double-layered metal nano-strips arrays. This system has the advantages of simple geometry and direct integration with microfluidic chips. The intense optical localization due to field coupling within the system can enhance detection sensitivity of target molecules, especially by virtue of the optical trapping of plasmonic nanoparticles. The optical resonant condition is obtained theoretically through analyzing the SPs modes. Numerical modeling based on two-dimensional (2D) finite-difference time-domain (FDTD) is consistent with the theoretical analysis and demonstrates the feasibility of using this system for optical sensing and trapping. Simulation results show that the refractive index sensitivity can reach ~200 nm/RIU, and a maximum SERS enhancement factor (EF) of 10⁹-10¹° is possible because of the near-field modulation and enhancement from optically trapped metal nanoparticles. / In the second design, a gold nano-ring structure is demonstrated to be an effective approach for plasmonic nano-optical tweezers (PNOTs) for trapping metallic nanoparticles. The plasmonic nano-ring structure has many interesting merits such as polarization insensitivity, wide tunable resonance range, uniform field enhancement around and inside the ring cavity, and ease of fabrication. This design has a unique feature of having large active volume for trapping. In our demonstration example, we have optimized a device for SERS operation at the wavelength of 785 nm. Three-dimensional (3D) FDTD techniques have been employed to calculate the optical response, and the optical force distribution have been derived using the Maxwell stress tensor (MST) method. Simulation results indicate that the nano-ring produces a maximum trapping potential well of ~32 kgT on a 20 nm gold nanoparticle. The existence of multiple potential well results in a very large active trapping volume of ~10⁶ nm³ for the target particles. Furthermore, the trapped gold nanoparticles further lead to the formation of nano-gaps that offer a near-field enhancement of ~160 times, resulting in an achievable EF of 10⁸ for SERS. / In the third design, we propose a concept of all-optical nano-manipulation. We show that target molecules, after being trapped, can be transferred between the trapping sites within a linear array of PNOTs. The system consists of an array of graded plasmonic nano-disks (NDs) with individual elements coded with different resonant wavelengths according to their dimensions. Thus, by switching the wavelength and rotating the polarization of the excitation source, the target nanoparticles trapped by the device can be manipulated from one ND to another. 3D FDTD simulation and MST calculation are utilized to demonstrate the operation of this idea. Our results reveal that the target experiences a trapping potential strength as high as 5000 kgT/W/μm², maximum optical torque of ~336 pN·nm/W/μm², and the total active volume may reach ~10⁶ nm³. The potential applications in terms of optical sensing are also discussed. / In the final design, for which experimental demonstration has been conducted, we show that PNOTs are achievable with random plasmonic nano-islands. Operation of the random PNOTs can be monitored by measuring the SERS enhancement factor in real time. Two laser beams having wavelengths of 633 nm and 785 nm are utilized to stimulate the PNOTs and excite the Raman signals simultaneously. The PNOTs are formed by annealing of a thermal evaporated gold film. This so-called nano-island substrate (Au-NIS) has a resonant peak close to 633 nm. The target is photochemical synthesized silver nanodecadedrons (AgNDs) functionalized with 4-Mercaptobenzoic acid (4-MBA) and the resonant peak of these AgNDs is far away from 633 nm and 785 nm. As the target is trapped to the hot-spots when the PNOTs are active, the near-field intensity is enhanced significantly, which results in the emergence of SERS signals, i.e. confirming the expected outcome of SERS upon nanotrapping by the PNOTs. This process is also elucidated numerically through 3D FDTD simulation and MST calculation. Furthermore, the target can be released as the PNOTs become inactive, i.e. disappearance of the SERS signal. Therefore, this design offers not only a robust avenue for monitoring trapping events in PNOTs, but also a reproducible “trap-and-sense“ platform for bio-detection. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Kang, Zhiwen. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 146-170). / Abstracts also in Chinese. / Abstract --- p.I / Acknowledgements --- p.VIII / List of Illustrations --- p.XIII / Chapter Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Surface Plasmon Polaritons and Localized Surface Plasmons --- p.1 / Chapter 1.2 --- Relevant Applications Based on Surface Plasmons --- p.3 / Chapter 1.3 --- Plasmonic Nano-Optical Tweezers and Relevant Applications --- p.7 / Chapter 1.4 --- Literatures Review and Objectives of this Thesis --- p.12 / Chapter 1.5 --- Structure of this Thesis --- p.17 / Chapter Chapter 2. --- Research Methodologies --- p.20 / Chapter 2.1 --- Theoretical Background of Surface Plasmons --- p.20 / Chapter 2.2 --- Numerical Simulation Techniques for Studying Complex Nanostructures --- p.30 / Chapter 2.3 --- Optical Force Calculation with the Maxwell Stress Tensor Method --- p.38 / Chapter 2.4 --- Nanostructure Fabrication and Characterization --- p.40 / Chapter Chapter 3. --- Optical Sensing Based on Double-Layered Metal Nano-Strips --- p.43 / Chapter 3.1 --- Introduction --- p.43 / Chapter 3.2 --- Theoretical Model and Analysis --- p.46 / Chapter 3.3 --- Numerical Verification and Discussion --- p.50 / Chapter 3.4 --- Optical Sensing Evaluation --- p.54 / Chapter 3.5 --- Near-Field Modulation by Optically Trapped Metal Nanoparticles --- p.58 / Chapter 3.6 --- Discussion --- p.61 / Chapter 3.7 --- Conclusion --- p.62 / Chapter Chapter 4. --- Gold Nano-Ring as Plasmonic Nano-Optical Tweezer --- p.64 / Chapter 4.1 --- Introduction --- p.64 / Chapter 4.2 --- Design and Optical Response --- p.67 / Chapter 4.3 --- Optical Force Calculation and Evaluation of Trapping Performance --- p.73 / Chapter 4.4 --- Stable Trapping Sites and Active Trapping Volume --- p.76 / Chapter 4.5 --- Near-Field Variation and Discussion --- p.81 / Chapter 4.6 --- Conclusion --- p.84 / Chapter Chapter 5. --- Graded Plasmonic Nano-Disks for Near-Field Nano-Manipulation --- p.86 / Chapter 5.1 --- Introduction --- p.86 / Chapter 5.2 --- Modeling and Optical Response --- p.89 / Chapter 5.3 --- Optical Force Distribution in the Structure --- p.91 / Chapter 5.4 --- Optical Trapping Potential and Rotational Energy --- p.96 / Chapter 5.5 --- Optical Trapping Volume and Discussion --- p.101 / Chapter 5.6 --- Conclusion --- p.104 / Chapter Chapter 6. --- Monitoring Plasmonic Nano-Optical Trapping through Detection of Surface-Enhanced Raman Scattering --- p.106 / Chapter 6.1 --- Introduction --- p.106 / Chapter 6.2 --- Numerical Investigation --- p.110 / Chapter 6.3 --- Sample Preparation and Characterization --- p.112 / Chapter 6.4 --- Experimental Implementation and Results --- p.122 / Chapter 6.5 --- Discussion --- p.134 / Chapter 6.6 --- Conclusion --- p.137 / Chapter Chapter 7. --- Conclusion and Outlook --- p.139 / References --- p.146 / Publications from this Work --- p.171

Iu, Hei = 二維週期性金屬納米共振腔的理論研究 / 姚熙. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 89-91). / Abstracts in English and Chinese. / Iu, Hei = Er wei zhou qi xing jin shu na mi gong zhen qiang de li lun yan jiu / Yao Xi. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Introduction to Surface Plasmon Polaritons --- p.3 / Chapter 2.1 --- The Maxwell´ةs Equations --- p.3 / Chapter 2.2 --- Photonic crystals --- p.5 / Chapter 2.3 --- Modeling Metal --- p.9 / Chapter 2.4 --- Surface plasmon polarition --- p.12 / Chapter 3 --- Rectangular Cavity --- p.17 / Chapter 3.1 --- Basic simulation cell setup --- p.17 / Chapter 3.2 --- Method of mode identification --- p.18 / Chapter 3.2.1 --- Dispersion relation calculation --- p.18 / Chapter 3.2.2 --- Reflection spectra --- p.19 / Chapter 3.3 --- Results and discussions --- p.20 / Chapter 4 --- Nano-bottle cavity --- p.25 / Chapter 4.1 --- Cylindrical cavity --- p.25 / Chapter 4.1.1 --- Dispersion relations calculation --- p.25 / Chapter 4.1.2 --- Field pattern calculation --- p.29 / Chapter 4.2 --- Nano-bottle cavity --- p.46 / Chapter 4.2.1 --- The effect of the bottleneck on (0，1) mode --- p.47 / Chapter 4.2.2 --- The effect of aperture size on (0，1) mode --- p.58 / Chapter 4.2.3 --- The effect of the depth of cavities on (0，1) mode --- p.62 / Chapter 4.2.4 --- "The effect of aperture size on (-1,0) mode" --- p.63 / Chapter 4.3 --- Discussions --- p.64 / Chapter 4.4 --- Verified with experimental results --- p.68 / Chapter 5 --- Aspect ratio --- p.71 / Chapter 5.1 --- Simulation structure --- p.72 / Chapter 5.2 --- Aspect ratio S = 2 --- p.73 / Chapter 5.3 --- The effect of aspect ratio --- p.74 / Chapter 5.3.1 --- Orientation dependence of the resonant mode --- p.74 / Chapter 5.3.2 --- Excitation frequency of the resonant mode --- p.75 / Chapter 5.4 --- Field location and strength --- p.76 / Chapter 5.5 --- Discussions --- p.77 / Chapter 5.6 --- Comparison with experimental results --- p.79 / Chapter 6 --- Conclusions and future works --- p.83 / Chapter 6.1 --- A possible new mode excitation --- p.84 / Chapter 6.2 --- Cavities with aspect ratio under p-polarized light --- p.86 / Bibliography --- p.89 / Chapter A --- Computational Simulation --- p.92 / Chapter A.l --- Finite-Difference Time-Domain --- p.92 / Chapter A.2 --- Computational grid --- p.93 / Chapter A.3 --- Boundary Condition --- p.93 / Chapter A.4 --- Source --- p.94 / Chapter A.5 --- Field strength --- p.94

With the development of ultra-fast laser technology, several new imaging techniques have pushed optical resolution past the diffraction limit for traditional light-based optics. Advancements in lithography have enabled the straightforward creation of micron- and nanometer-sized optical devices. Exposing metal-dielectric structures to light can result in surface plasmon excitation and propagation along the transition interface, creating a surface plasmon polariton (SPP) response. Varying the materials or geometry of the structures, the plasmonic response can be tailored for a wide range of applications. Photoemission electron microscopy (PEEM) has been used to image excitations in micron-sized plasmonic devices. With PEEM, optical responses can be characterized in detail, aiding in the development of new types of plasmonic structures and their applications. We show here that in thin, triangular gold platelets SPPs can be excited and concentrated within specific regions of the material (thickness ~50 nm); resulting in localized photoemission in areas of high electric field intensity. In this regard, the platelets behave as receiver antennas by converting the incident light into localized excitations in specific regions of the gold platelets. The excited areas can be significantly smaller than the wavelength of the incident light (λ≤1µ). By varying the wavelength of the light, the brightness of the excited spots can be changed and by varying the polarization of the light, the brightness and position can be changed, effectively switching the photoemission on or off for a specific region within the triangular gold structure. In this work, the spatial distribution of surface plasmons and the imaging results from photoemission electron microscopy are reproduced in simulation using finite element analysis (FEA). In addition, we show that electromagnetic theory and simulation enable a detailed and quantitative analysis of the excited SPP modes, an explanation of the overall optical responses seen in PEEM images, and prediction of new results.

The optical response of metallic structures is dominated by the dynamics of their free electron plasma. Plasmonics, the area of optics specializing in the electromagnetic behavior of heterogeneous structures with metallic inclusions, is undergoing rapid development, fueled in part by recent progress in experimental fabrication techniques and novel theoretical approaches. In this thesis I outline the behavior of four plasmonic material systems, and discuss the underlying physics that governs their optical response. First, the anomalous optical properties of solution-derived percolation films are explained using scaling theory. Second, a novel technique is developed to characterize the optics of amorphous nanolaminates, leading to the creation of a meta-material with anisotropic (hyperbolic) dispersion. The properties of such materials can be tuned by adjusting their composition. Third, the electrodynamics of vertically aligned multi-walled carbon nanotubes is derived through the development of a spectroscopic terahertz transmission ellipsometry algorithm. Lastly, a new diffraction based imaging structure based on metallic gratings is presented to have resolution capabilities which far outperform the diffraction limit. / Graduation date: 2013

No description available.

No description available.

Thesis (Ph. D.)--University of Washington, 1993. / Vita. Includes bibliographical references (leaves [147]-149).

Thesis (M. S.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2008. / Committee Chair: El-Sayed, Mostafa A.; Committee Member: Lyon, L. Andrew; Committee Member: Sherrill, C. David; Committee Member: Wang, Zhong Lin; Committee Member: Whetten, Robert L.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.