This thesis concerns the application of seismic interferometry to surface waves. Seismic interferometry is the process by which the wavefield between two recording locations is estimated, resulting in new recordings at one location as if a source had been placed at the other. Thus, in surface-wave interferometry, surface waves propagating between two receiver locations are estimated as if one receiver had recorded the response due to a source of surface-wave energy at the other receiver. In global and engineering seismology new surface-wave responses can allow for imaging of the subsurface, and in exploration seismology it has been proposed that these new surface-wave responses can allow for the prediction and removal of socalled ground-roll (surface waves that are treated as noise). This thesis presents a detailed analysis of surface-wave interferometry: using a combination of modelling studies, real-data studies, and theoretical analyses the processes involved in the application of interferometry to complex (both multi-mode and scattered) surface waves are revealed. These analyses identify why surface waves are often dominant in the application of interferometry, where errors may be introduced in the application of surface-wave interferometry, and how interferometry may be processed in such a way as to minimise those (and other) errors. This allows for the proposal of new data-processing strategies in the application of seismic interferometry to surface waves, potentially resulting in improved surface-wave estimates. Much of the work in this thesis focuses on the use of seismic interferometry to predict and subtract surface waves in land-seismic exploration surveys. Using insights from the presented analyses it is shown that seismic surface waves can be successfully predicted and removed from land-seismic data using an interferometric approach. However, the work in this thesis is not only limited to applications in exploration seismology. In addition to the ground-roll removal method, improved estimates of higher-mode and scattered surfaces waves may allow for more advanced imaging algorithms to be used in conjunction with seismic interferometry. Also, as a consequence of the analysis presented a Generalized Optical Theorem for Surface Waves is derived. This highlights a link between seismic interferometry and the optical theorem and may allow for further application of optical theorems in seismology.

Although surfactant selective electrodes have been employed for several decades, those electrodes "of the second kind" and those incorporating a liquid membrane suffered severe limitations. A large improvement in the reliability of such electrodes was achieved by Cutler (Ph.D. Thesis, University of Aberdeen, 1975) using a liquid plasticized PVC membrane in which the surfactant was directly complexed to the PVC. However, such electrodes still had several drawbacks including the solubilisation of the liquid plasticiser from the membrane and the influx of water through the membrane after only a few hours in solution. It was the purpose of this study to reproduce and perhaps improve upon the electrodes developed by Cutler and to use them to investigate the thermodynamics of colloidal ionic surfactant solutions. Initially, the electrodes developed for both cationic and anionic surfactants by Cutler were reproduced and during the course of the study were improved upon by replacing the liquid plasticizer content of the membranes by a high molecular weight PVC-compatible terpolymer. This polymeric blended membrane is much tougher than the liquid plasticized one and has a much higher resistance to the uptake of water. Thus, the useful lifetime of a membrane was extended from a period of hours to a period of weeks. In addition the polymer blended membrane has no liquid components and hence the solubilisation of membrane component in micellar solution is no longer a problem. The surfactant selective electrodes was used in conjunction with electrodes reversible to other common species in solution (Na+, Cl-, Br-, etc.) to construct cells without liquid junction for potential measurements. In addition to getting rid of the unavoidable error associated with potential measurements using cells with liquid junction, this experiment allowed for a direct determination of the surfactant monomer concentration above the CMC. This is, to the authors knowledge, the first time that such a measurement has been experimentally possible. Initially a well documented system was chosen for investigation: the micellisation of sodium dodecyl-sulphate in aqueous salt (NaBr) solutions. The well known depression of the CMC with increasing salt concentration was observed and from this the degree of dissociation of counterions from the micelles was calculated. This corresponded closely to other values reported in the literature. Recently a thermodynamic theory of the micellisation of ionic surfactants has been reported by Hall (1981) and using data obtained by the electrode measurements, three tests of the theory were possible. In each case the theory was found to correspond with the experimental measurements. Additionally using the electrode measurements it was possible to estimate the interaction or 'Harned' coefficient between the dodecylsulphate and sodium ions in aqueous salt solutions below the CMC. The use of the electrodes was extended to other 'non detergent' amphiphilic molecules and the aggregation of BDPH, a cationic drug, was investigated. These molecules were found to form pre-micelles before the onset of true micellisation and an iterative simulation procedure indicated that these pre-micelles were probably dimers. The effect of salt upon the CMC was also determined and hence, α, the degree of dissociation of counterions from the micelles was calculated. This value agreed well with other literature reports. The electrodes were also used to investigate the aggregation of ionic surfactants in mixed solvent media e.g. ethylene glycol + water and ethanol + water mixtures. The variation of a with solvent composition was observed and additionally it was demonstrated that the electrode measurements could be used to determine conveniently the solubility product of ionic surfactants in aqueous or mixed solvent systems. Mixed micellar systems were also studied. These included anionic-cationic, ionic-nonionic and ionic-zwitterionic systems and the composition of the mixed micelles in many cases was found to follow a very simple model based upon the regular mixing of the micellar components. The phase behaviour of these systems was also observed since many of them were found to form stable micelles only at certain compositions. Phase separation including precipitation, coacervation or liquid crystalline phase formation was found in many systems over certain solution compositions. The electrodes were used to calculate the α value of a mixed micellar system as a function of micelle composition. In the final chapter the binding of ionic surfactants to synthetic macromolecules is discussed and the results of electrode measurements are reported. The measurement of the adsorption isotherm of the surfactant into the polymer was found to be very quick and convenient and the systems investigated included both anionic and cationic surfactants binding onto either neutral polymers or highly charged polyelectrolytes. The effect of the solution composition variables (i.e. salt, surfactant and polymer concentrations) and the molecular weight of the polymer upon the binding process was determined for one system, sodium dodecylsulphate binding to polyvinylpyrollidene. A recent theory by Hall to account for the binding of ionic surfactant to neutral polymers is discussed and experiments were carried out to test this theory.

Lors d’une rentrée atmosphérique, les boucliers thermiques des véhicules spatiaux subissent un échauffement considérable dont une fraction significative (~30%) est attribuée aux réactions chimiques à leur surface. Cette thèse contribue à la compréhension de cette réactivité hétérogène, la catalycité, au moyen des outils de la chimie théorique. Une méthode de construction de surface d’énergie potentielle globale est développée et appliquée à l’étude de la dynamique de processus élémentaires (adsorption moléculaire dissociative, absorption atomique, recombinaison Eley-Rideal …) pour les systèmes chimiques N,N2/W(100,110) et O,O2/Cu(100). Ces approches sont ensuite couplées à un modèle cinétique permettant de quantifier la catalycité. / During an atmospheric re-entry, the thermal shields of spacecrafts undergo an important heating, a significant fraction (~30%) of which is due to the chemical reactions at their surface. This thesis is a contribution to the understanding of this heterogeneous reactivity, catalycity, with the tools of theoretical chemistry. A method to build a global potential energy surface is developed and applied to the study of elementary processes dynamics (dissociative molecular adsorption, atomic absorption, Eley-Rideal recombination …) for the N,N2/W(100,110) and O,O2/Cu(100) chemical systems. These approaches are then coupled with a kinetic model quantifying catalycity.

We quantified the chemical species present at polycrystalline cesium tin bromide perovskite, CsSnBr3 and cesium titanium bromide antifluorite, Cs2TiBr6. For CsSnBr3, experiments utilized the orthogonal reactivity of the Cs+ cation, the Sn2+ cation, and the Br– halide anion. Ambient- pressure exposure to BF3 solutions probed the reactivity of interfacial bromines. Reactions with p-trifluoromethylanilinium chloride probed the exchange reactivity of the Cs+ cation. A complex-forming ligand, 4,4’-bis(trifluoromethyl)-2,2’-bipyridine, probed for interfacial Sn2+- site cations. For Cs2TiBr6, both BF3 and (C6F5)3B probed the reactivity of interfacial bromines. Fluorine features in x-ray photoelectron spectroscopy (XPS) quantified reaction outcomes for each solution-phase species. XPS indicated adsorption of BF3 on CsSnBr3 and (C6F5)3B on Cs2TiBr6 indicating surface-available halide anions on both surfaces. For CsSnBr3, temperature- programmed desorption (TPD) quantified a ~215 kJ mol–1 desorption energy of BF3 on the surface. Adsorption of the fluorinated anilinium cation included no concomitant adsorption of chlorine as revealed by the absence of Cl 2p features within the limits of XPS detection. The bipyridine ligand demonstrated adsorption to CsSnBr3. We discuss the present results in the context of interfacial stability, passivation, and reactivity for solar-energy conversion devices.

We quantified the chemical species present at polycrystalline cesium tin bromide perovskite, CsSnBr3 and cesium titanium bromide antifluorite, Cs2TiBr6. For CsSnBr3, experiments utilized the orthogonal reactivity of the Cs+ cation, the Sn2+ cation, and the Br– halide anion. Ambient- pressure exposure to BF3 solutions probed the reactivity of interfacial bromines. Reactions with p-trifluoromethylanilinium chloride probed the exchange reactivity of the Cs+ cation. A complex-forming ligand, 4,4’-bis(trifluoromethyl)-2,2’-bipyridine, probed for interfacial Sn2+- site cations. For Cs2TiBr6, both BF3 and (C6F5)3B probed the reactivity of interfacial bromines. Fluorine features in x-ray photoelectron spectroscopy (XPS) quantified reaction outcomes for each solution-phase species. XPS indicated adsorption of BF3 on CsSnBr3 and (C6F5)3B on Cs2TiBr6 indicating surface-available halide anions on both surfaces. For CsSnBr3, temperature- programmed desorption (TPD) quantified a ~215 kJ mol–1 desorption energy of BF3 on the surface. Adsorption of the fluorinated anilinium cation included no concomitant adsorption of chlorine as revealed by the absence of Cl 2p features within the limits of XPS detection. The bipyridine ligand demonstrated adsorption to CsSnBr3. We discuss the present results in the context of interfacial stability, passivation, and reactivity for solar-energy conversion devices.

A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Engineering. / The viability of introducing a Surface Mount production line is chiefly determined by the reliability characteristics of the components being used. Surface Mount Technology (SMT) is entirely new and although related to traditional through-hole processes, requires different components, assembly techniques and design methods. The purpose of the literature survey is primarily to determine whether surface mount components meet today's industrial requirements with respect to their manufacturing reliability and availability. A brief review of the evolution of SMT is also presented. This study finds that the implementation of SMT should be given highest priority by manufacturing companies in order to maintain their share of the marketplace. Surface Mount Technology embodies a totally new automated circuit assembly process, using a new generation of electronic comporents: surface mounted devices (SMDs). Smaller than conventional components, SMDs are placed onto the surface of the substrate. From this, the fundamental difference between SMD assembly and convencional through-hole component assembly arises; SMD component positioning is relative, not absolute. When a through-hole component is inserted into a pcb, either the leads go through the hales or they don't. An SMD, however, is placed onto the substrate surface, it's position only relative to the solder lands, and placement accuracy is therefore influenced by variations in the substrate track pattern, component size, and placement machine accuracy. Other factors influence the layout of SMD substrates. For example, will the board be a mixed-print ( a combination of through-hole components and SMDs) or an all-SMD design? Will SMDs be placed on one side of the substrate or both? And there are process considerations like what type of machine will place the components and how will they be soldered? This project describes in detail the processes involved in setting up an SMT facility. A simulation program was developed to verify the viability of these processes. The simulation program was also applied to an existing SMT facility and together with developed optimization software, attempted to identify and resolve some of the major problems. All this was achieved, and the extent to which simulation could be used as an efficient production tool, was highlighted. / AC2017

In this thesis, four experimental studies are reported. Two concern the surface structure of commercially relevant dental implant materials. Characterisation of four treated substrates supplied by Straumann AG was carried out. These include substrates equivalent to the commercially available SLA, SLActive and Roxolid implants. The materials vary in substrate alloy, commercially pure (grade 2) Ti and a TiZr alloy, and surface preparation treatments. All substrates are sandblasted and acid etched however post-etching one set are stored in air whilst the others are stored in saline. Within the work both substrate composition and surface treatment is shown to impact on the respective surface oxide thickness, crystallinity and morphology. The other two experimental studies concern calcium phosphate deposition from solution onto substrates. The first investigation is the deposition of calcium phosphate from a simulated body fluid onto implant-like substrates, shown to be structurally equivalent to the SLA and SLActive implant surfaces. The effect of surface modifications on calcium phosphate deposition is investigated; over the period investigated calcium phosphate did not deposit onto the SLA substrate, whilst deposition occurred within 3 days on the SLActive substrate. The role of Mg2+ ions in the simulated body fluid is also investigated, with increased [Mg2+] resulting in a longer induction period and modified crystallinity of the hydroxyapatite film formed. The final study is a model study of the initial calcium phosphate deposition on to substrates. TiO2 rutile (110) and Al2O3 corundum (0001) were prepared to be atomically flat and then exposed to a simple calcium phosphate solution. Changes in surface structure and surface chemistry over the first three hours of exposure were investigated. Deposition occurred rapidly on both substrates with a complete surface coverage after 3 hours.

硅對現今科技至關重要。而有機物吸附於硅表面可能大大擴展硅的用途。在本論文中，我採用密度泛函理論研究了六種分子於硅表面的反應。本論文大致可分為四部分。 / 第一部分包含四個分子（吡嗪、吡啶、嘧啶與1,3,5-三氮嗪）的吸附研究。它們都擁有類似於苯的結構而環中又包含氮原子。分子可以用氮原子與表面形成配位鍵並作為進一步反應的前體故其反應更為容易預測。而反應通常只消除π 鍵而不會使分子分解這使得分子可以在平衡狀態下與表面生成最為穩定的結構。此兩種特性使它們成為硅表面吸附的絶佳研究對象。不同的實驗都顯示出吡嗪於硅表面只會生成Cross-row bridge 結構加熱硅表面更會促進納米線的生成。過往的計算無法解釋實驗結果而我的計算表明范德華力對導出正確計算結果非常重要加入范德華力的修正可以同時解釋單一產物與納米線的生成。吡啶的吸附實驗結果相比之下較為複雜。低溫下的吸附與飽和只生成兩種產物可是室溫下的實驗卻顯示多種產物並存於表面。加入范德華力的計算結果指出覆蓋度和溫度與吸附密切相關並指出對低溫下形成的飽和表面加溫可能促使納米線的生成。而於室溫下吡啶可進入多條反應路徑致使多種產物於表面並存。基於范德華力對這兩個分子的顯著影響我又將此效應加諸於嘧啶與1,3,5-三氮嗪的吸附研究。結果表明於低覆蓋度與低溫下它們只生成Double-dative 產物。然而增加覆蓋度會使Double-dative 的能量高於其它產物導致多種產物並存。由於嘧啶與1,3,5-三氮嗪都可生成一種特別的tight-bridge 結構加溫會使它們輕易解離。對此四種分子的研究顯示出氮原子的數量與位置如何影響吸附過程。 / 第二部分包含對1,2-環己二酮的吸附研究。於室溫下此分子會以互變異構體形式存在。之前的實驗指出它會先變回二酮才進行後續反應這種硅表面輔助互變反應的現象是前所未見的卻無後續研究以驗証其說。我的計算結果指出雖然互變反應的能壘被硅表面大幅降低可是仍不足以與其他反應路徑相匹敵。其中三種新產物既與實驗譜相吻合而反應能壘和能量都低故比之前所提產物更為可取。 / 第三部分包含對氰基苯的吸附研究。之前的三個實驗給出完全不同的結論。探明其與覆蓋度和溫度的關係後我提出氰基苯於低溫下飽和只會生成一種產物。而在室溫下的吸附會先生成valley-bridge 結構增加覆蓋度將使多種產物並存。計算結果不但表明有序吸附的可能性同時又解釋為何不同實驗給出看似不相容的結論。 / Silicon is an important material and substrate in modern technologies. Adsorption of organic molecules on silicon surface has attracted much attention due to the possibility of functionalizing the surface. In this thesis, density functional theory has been applied to study the adsorption of several organic molecules on Si(100) surface. / Results on the adsorption of benzene-like N-heteroaromatic molecules on Si(100)surface, including pyrazine, pyridine, pyrimidine and s-triazine, are presented in Chapters 2-4. This class of molecules, containing nitrogen atoms, can datively attach to dimer and act as precursor for further reaction. Thus, their reactions on surface can be easily predicted. Their reaction with surface would sacrifice π bond rather than dissociation under very mild condition such that the most stable adsorption product can be obtained under thermal equilibrium. These two properties of N-heteroaromatic compounds makes them good models for the study of reaction on surface Experiments repeatedly showed that pyrazines formed cross-row bridge structures on Si(100) under various conditions, and thermal annealing led to the formation of ordered nano-lines. Previous calculations did not explain these observations. This thesis demonstrates that addition of van der Waals (vdW) correction is critical to explain the formation of both the cross-row bridge and the nano-lines. For pyridine, the situation is more complex. Only two products were observed in low temperature adsorption experiments. In contrast, room temperature experiments yielded a mixture of products. With vdW corrections added, results show that pyridine adsorption is dependent on both coverage and temperature. Adsorption and saturation started at low temperature and followed by annealing may produce nano-lines consisted of cross-row bridge structures. Adsorption at room temperature opens up all reaction channels such that nano-line formation becomes difficult, which explains the discrepancy among experimental studies. In light of these results, the pyrimidine and s-triazine adsorption on Si(100) are also explored. The results show that they form double-dative structures at low coverage and low temperature. Increasing coverage will destabilize it and lead to mixture of products. These structures decompose easily upon heating due to the formation of a particular tight-bridge structure. These results show that the position and number of heteroatom are important to explain the difference in reaction selectivity among N-heteroaromatic molecules. For all four molecules, cooperative effect and the addition of vdW correction, which are almost neglected in similar study, are shown to be important in surface adsorption process. / In Chapter 5, the adsorption of 1,2-cyclohexanedione (1,2-CHD) on surface is studied. Gas molecule of 1,2-CHD exists in the tautomeric form (2-hydroxylcyclohex-2-ene-1-one) at room temperature. Previous experimental studies claimed that surface assisted tautomerization back to 1,2-CHD took place before further reaction, although there was no follow-up study. Computational results showed that although surface adsorption lowers the barrier for tautomerization, the barrier is still at least 5 times larger than other reaction channels. Three new structures are proposed, which are in better agreement with previous spectroscopic results. / In the final chapter, the adsorption of benzonitrile on Si(100) is studied. Three previous experimental studies presented conflicting results. With the coverage and temperature dependence effects clarified, my results suggest that adsorption at saturation and low temperature leads to a single product. Adsorption at room temperature first leads to a valley-bridge structure, while a mixture of adsorption structures is produced upon increasing coverage, which explained the conflicting experimental results. The last two chapters show the importance of computational modeling for interpretation and summarizing experimental results. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Ng, Kwok Hung. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references. / Abstracts also in Chinese. / Ng, Kwok Hung.

近年來，表面等離子體因為可以在金屬表面激發極強的局部電磁場而受到廣泛的關注。它是光和物質之間的重要的聯繫。基於它在納米量級上操控和引導光子的能力，表面等離子體已廣泛應用于納米和生物光學之中，比如生物傳感器，表面增強拉曼散射，光鑷，發光二極管，太陽能電池和超材料等等。然而，儘管系統結構，材料特性，激發光波長和條件都會影響表面等離子體本身的特性以及它與材料之間的相互作用，這些外部條件的整體效果卻常常不為人所知。更重要的是，在表面等離子體和這些外部條件之間，似乎仍有未知的聯繫存在。比如，現在人們仍然不是很清楚激發表面等離子體的納米結構到底是怎樣控制它以及與它相關的特性的。 / 在這篇論文里，我們希望通過耦合模理論將這些外部條件和表面等離子體特性聯繫起來。耦合模理論提供了表面等離子體吸收和輻射壽命等內部參數以及它們與光相位，振幅，傳播方向的關係。因為這些外部條件和壽命參數，激發條件之間的聯繫廣為人知，我們因此就可以把這些外部條件和表面等離子體特性聯繫起來了。一旦獲得了這些壽命參數，我們亦可從另外一個角度研究表面等離子體的基本特性。比如，我們發現兩個簡併表面等離子體耦合除了形成超模式和次模式以外，它們的輻射壽命和吸收壽命都發生了改變。另外，我們在實空間和動量空間研究了表面等離子體衰變長度，群速度等其他內部參數，并發現它們和等離子體衰減及態密度有重要聯繫。我們還發現基於相位躍變的表面等離子體傳感器在臨界耦合時將獲得最優表現。最後，通過研究發光材料和表面等離子體之間的耦合效率，我們發現態密度在其中起了關鍵作用。 / Surface plasmons (SPs), which generate strong localized electromagnetic fields at metal surface, have been capturing worldwide attention recently because they establish an important link between light and matter. Due to their ability to route and manipulate photon at the nanoscale, SPs have been widely used in nano- and bio-photonics including biosensor, surface enhanced Raman scattering, optical tweezers, light emitting diodes, solar cell, and metamaterials, etc. However, although it is known that system geometry, material, wavelength, excitation condition are important in governing the behaviors of SPs as well as matter/SPPs interactions, how they work together in producing the final outcome is largely unknown. More importantly, there seems to be a "missing link" between these extrinsic parameters and the properties of SPs such that, for example, it is still not quite understood the exact roles of geometry play in controlling the SPs and their related properties. / In this thesis, we aim at bridging the link between extrinsic parameters and SPs properties based on temporal coupled-mode theory (CMT). CMT provides the knowledge of intrinsic parameters such as SPs radiative and absorption rates and their relationships with the phase, amplitude, and directionality of SPs. Because decay rates are strong function of system parameters, excitation condition, etc, connection between the extrinsic parameters and the SPs properties can now be established. With the decay rates and other accessories in hand, we study the fundamental of SPs from another perspective. For example, we examine how two degenerate SPs modes couple to yield a pair of dark and bright modes and find not only the radiation damping of SPs but also the absorption are modified. In addition, we study the decay length and the group velocity of SPs in real- and momentum- space to elucidate the interplay between the SPs losses and the wavevector-resolved projected density-of-optical-states (PDOS). We also explore the rate matching (i.e. critical coupling) for optimizing the phase-jump in SPs resonance sensing and achieve high figure of merit in sensing performance. Finally, the coupling between SPs and light emitters has been studied and it is found that their coupling rate is governed by PDOS. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Cao, Zhaolong = 表面等離子體激元在金屬納米洞陣列上的衰變研究及其應用 / 曹兆龍. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 142-149). / Abstracts also in Chinese. / Cao, Zhaolong = Biao mian deng li zi ti ji yuan zai jin shu na mi dong zhen lie shang de shuai bian yan jiu ji qi ying yong / Cao Zhaolong.

表面電漿是由貴金屬表面電荷密度漲落引起的沿著金屬表面傳播的電磁波。在過去十年裡，表面電漿效應因其在光子器件，傳感，表面增強螢光，尤其是表面增強拉曼散射(SERS) 方面的應用而引起了廣泛的關注.許多著作中的結論已經證實了的預期的SERS 強度，因此使得基於各種不同納米結構中的熱點的SERS變成一種下一代超敏感生物傳感平臺。因為表面電漿的波長和材料介電性質密切相闕，受f於此，難以進一步減小，所以對於進一步的各種應用來說，保證產生高強度的表面電漿使至關重要。同時，用電漿實現納米光子器件已經引起了研完者長久的興趣。例如，基於等問距規則排列的密置金屬納米顆粒之間突破衍射極限的的近場耕合已經被用於傳輸光信號。但是，輻射和吸收損耗在此類波導中是很嚴重的。因此，設計新概念的電漿器件是急需的。 / 有鑒於上述種種問題，本論文集中于總結構和材料兩方面剪裁表面電漿以期達到下面的要點和目的: / (1)基於傳播電漿(PSPs) ，或者傳播電漿同局域電漿(LPRs) 的結合而發展新的簡單的器件，由此提供顯著的聚焦、電磁場和場強增強。這種器件可以應用於很多方面，包括依賴強場的生物分子傳感探測，以及非線性光學效應。 / (2) 設計基於增益介臂的低損耗的納米光子學器件，這種器件能夠為納米光子器件提供切實的可行性。針對表面電漿共振和電漿結構植于的介電環境之間聯繫，獲得其理論闡釋。這一工作將可以為傳感和器件設計提供深入的理解。 / 本論文中我們已經得到了如下的成果: / (1)一種基於將表面電漿聚焦到金屬盤中心孔而實現級聯放大增強的SERS 激勵源被提出和理論研究。這種器件提供了準均勻，水平偏振，較大面積的強SERS 激勵源。如時域有限差分(FDTD) 方法所揭試，強度譜線和波長範圍在650-1000 nm的近場性質展混出了一系列增強模式。在最佳的增強模式下，孔洞中的電場可以使得SERS 信號獲得四次方的進一步增強。同時一種解析模型也被提出來給FDTD結果以精確的解釋。我們的模型同時揭示了通過侵化金屬盤尺度而得到八次方場增強的可能性。我們的結果表明極強的電場增強，並且聚焦的電場是平行于金屬盤平面的效果，只能在中間包含一個孔洞的中空金屬盤(HMDs) 中才可能實現。這是因為金屬盤中間絶悸的問時的存在使得孔洞邊棒的電子不能流通間隙，進進而使得高強度的電場可以存在。另一方面，在實心的金屬盤的情形下，電子流會傾向於抑制到達中心的表面電漿的強度。除了產生高度優化的SERS 熱點，這種大面積的活性孔洞在螢光增強和非線性光學中也提供了一些潛在的應用。 / 除了中空金屬盤，基於經由增孟輔助下PSPs 的LPRs 之間的衍射共掠，我們開發了另一種一種高度侵化的熱點。由此得到的器件被理論上分析。衍射共振的過程是經由下述過程實現的:由LPRs 實現的光場局域化， LPRs 和PSPs 相互作用，以及通過PSPs 的能量傳遞。我們的研究表明通過給PSPs 引入光學增孟，可以從一種激光過程中的到LPRs 非常強的電磁場增強。我們發現通過現實的增豆豆水平，局域電場的增強引子可以達到10⁷。因此，我們為實現依賴強電場的單分子SERS提供了一種理想的方案，並且這種方案也是一種納米激光的新機制。 / (2) 基於增孟輔助的電漿共振金屬納米顆粒鏈，我們提出了一種低損耗納米尺度的波導。我們證明通過引入增孟材料或者引入適當的介電材料作為周圍環境，波導的損耗可以顯著減小。為了得到低損耗傳翰的復介電譜，我們開發了一種高效的膺正交基展開(POBE) 方法。本徵模式分析揭示了低損耗模式的物理源頭，同時給出了除了基於單體偶極共振傳輸之外能量傳輸的可能性。我們提出一種基於電子書刻蝕和化學合成納米顆粒的一種製備方案。這種電漿波導可以構成納米光學器件的基石，尤其是用於集成納米光子學線路。同時，我們原創的揭示表面電漿的物理機理的POBE 方法可以用於進一步研究優化增豆豆輔助的電漿結構，進而設計良好的納米光子器件。 / 本論文始於一個古老問題:宏觀尺度下基於傳統介電材料光聚焦和傳導，并最後終結於納米尺度內經由增益材料和電漿結構的表面電漿的聚焦、和引導。論文結尾，本文給出了展望以及幾種可能的器件實現方案。 / Surface plasmons (SPs) are electromagnetic waves that propagate along the surface of a noble metal via fluctuations in electron density. In the last decade, SPs effects gained widespread attention for their potential application in photonic devices, sensing, surface-enhanced fluorescence, especially Surface-Enhanced Raman Scattering (SERS). Many published results have confirmed the expected strengths of SERS, hence making it possible for SERS to become a next generation ultra-sensitive biosensing platform, which may take the form of various nano-structures in order to achieve optimized hot spots. While the wavelength of SPs is closely related to material dielectric properties and has limited scope for further reduction, it is of critical importance to ensure that SPs are being generated with the highest intensity before any further application advancement is possible. Meanwhile, plasmonics has aroused longstanding interests among researchers to realize nanophotonic devices. For example, ordered arrays of closely spaced metallic nanoparticles (MNP) have been employed to transport optical signals via near-field coupling below the diffraction limit. However, radiation and absorption losses in these waveguides can be serious. New concepts for novel plasmonic devices are essential. / In light of these issues, this thesis focuses on tailoring SPs from the viewpoints of structural and material properties with the following objectives: / (1) To develop a new class of simple plasmonic devices based on tailoring of propagating surface plasmons (PSPs) or cooperation between PSPs and localized plasmon resonance (LPRs) to offer significant field focusing and intensity enhancement. It can serve a wide range of applications, including high field related biomolecular sensing and detection as well as non-linear optical effects. / (2) To design low loss nanophotonic wave guides based on gain medium, which may offer real opportunity for practical nanophotonic devices. To obtain a theoretical interpretation of relationship between surface plasmon resonance and host environment where the plasmonic structure embedded. This study should provide further insight towards sensing and device design. / We have achieved the following results in this project: / (1) A novel SERS excitation source based on focusing of surface plasmons around the center hole of a metal disk for cascaded enhancement is put forward and studied theoretically. The device offers intense SERS excitation with quasi-uniformity and horizontal polarization over a comparatively large hole. As revealed by fmite-difference time-domain (FDTD) method, the intensity spectra and the characteristics of the near field for the wavelength range of 650-1 000 nm exhibit a number of enhancement modes. Electric field intensity of the optimal mode enhances the SERS signal inside the hole by over four orders. An analytical model was also developed to gain precise interpretation on FDTD results. Our model also reveals the possibility of achieving eight orders of enhancement by optimizing the scale of the disk. Our results indicate that much higher electric field enhancement in hollow metal disks (HMDs) can only be possible when we have a hole at the centre and the direction of the focusing field is parallel to the surface of the plasmonic device. This is because of the presence of an insulating gap at the center, that higher level of electric field can exist as electrons are not allowed to flow pass the gap. On the other hand, in the case of a solid metal disk, the flow of mobile electron will tend to dampen the amplitude of the arriving SPs. In addition to generation of highly optimized hot spots for SERS, the large active hole also offers potential applications in fluorescence enhancement and nonlinear spectroscopy. / In addition to HMDs, we also develop a kind of highly optimized hot spots based on diffraction coupling between LPRs via gain-assisted PSPs. Thus derived device was theoretically analyzed. The process of diffraction coupling is achieved via localization of light by LPRs, LPRs-PSPs interplay and PSPs transfer. Our study shows that by incorporating optical gain to PSPs, a very strong boost of the electromagnetic enhancement of LPRs can be expected from a lasing process. We find that with a practical gain level, the enhancement factor of local electric field intensity can be larger than 10⁷. Hence, we offer an ideal configuration to realize high-field dependent single molecule SERS and also a newly applied physical scheme for nano-Iaser. / (2) We propose a low-loss nanoscale wave guide based on gain-assisted plasmonic resonance MNP chain. We demonstrate that by employing a gain material or even an appropriate dielectric for the host environment, waveguide loss can be reduced dramatically. A highly efficient pseudo-orthonormal basis expansion (POBE) method for obtaining the complex dielectric spectra of the low-loss transmission has been developed. Eigenmode analysis revealed the physical origin of those low-loss wave guiding modes, which opens the possibility to achieve waveguiding other than using conventional dipolar resonances of individual particles. A scheme based on electron beam lithography and chemically synthesized nanoparticles has been proposed to fabricate the device. Such plasmonic waveguides may serve as building blocks for making nanoscale optical devices especially for integrated nanophotonic circuits. Meanwhile, the originally developed POBE method, which reveals the general physical mechanism of SPs, can be used to further explore optimized gain-assisted plasmonic structures to design favorable nanophotonic devices. / This thesis begins with an old problem: light focusing and guiding in macroscopic scale with traditional dielectric, and sum up finally with SPs focusing and guiding in nanoscale with gain material and plasmonic material. An outlook is presented at last with several potential schemes for the device realization. / 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. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Zhang, Haixi. / "September 2011." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 124-139). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Chapter Chapter1 --- Introduction --- p.1 / Chapter 1.1 --- Towards field intensity focusing and guiding of electromagnetic wave --- p.1 / Chapter 1.2 --- Surface plasmons as a route to realize electromagnetic field focusing and waveguiding in nanoscale --- p.3 / Chapter 1.3 --- Structure of this thesis --- p.10 / Chapter Chapter2 --- Plasmonic near field engineering: structural and material aspects --- p.13 / Chapter 2.1 --- Light focusing using near field oflocalized plasmon resonances --- p.13 / Chapter 2.2 --- Plasmonic near field focusing through propagating surface plasmons --- p.30 / Chapter 2.3 --- Various schemes for near field focusing through surface plasmons --- p.33 / Chapter 2.4 --- Guiding surface plasmons in nanoscale --- p.35 / Chapter 2.5 --- Gain-assisted surface plasmons: a different path to field enhancement and guiding --- p.38 / Chapter Chapter3 --- Surface plasmons: characteristics and methodology --- p.42 / Chapter 3.1 --- Characteristics of localized plasmon resonance --- p.42 / Chapter 3.2 --- Localized plasmon resonance: Mie theory and its variations --- p.44 / Chapter 3.3 --- Characteristics of propagating surface plasmons --- p.49 / Chapter 3.4 --- Reflection Pole Method for studying propagating surface plasmons in multilayer structures --- p.55 / Chapter 3.5 --- Pseudo-orthonormal basis expansion method: a new mathematical scheme for modeling surface plasmons --- p.58 / Chapter Chapter4 --- High field generation through intensity focusing of propagating surface plasmons --- p.62 / Chapter 4.1 --- Introduction --- p.62 / Chapter 4.2 --- The hollow metal disk design and its characteristics --- p.64 / Chapter 4.3 --- Quasi-uniform excitation source based on focusing of propagating surface plasmons for cascade enhancement of surface enhanced Raman scattering --- p.68 / Chapter 4.4 --- Conclusions and outlook --- p.78 / Chapter Chapter5 --- High field generation through intensity enhancement of localized plasmon resonance from gain-assisted diffraction coupling --- p.81 / Chapter 5.1 --- Introduction --- p.81 / Chapter 5.2 --- Diffraction excitation of localized plasmon resonance from propagating surface plasmons --- p.83 / Chapter 5.3 --- Diffraction coupling of localized plasmon resonance through gain-assisted propagating surface plasmons --- p.89 / Chapter Chapter6 --- Gain-assisted plasmonic waveguides based on nanoparticle chains: an effective device approach for achieving low loss in nanoscale dimensions --- p.97 / Chapter 6.1 --- Introduction --- p.97 / Chapter 6.2 --- Theoretical study of near-field particle interactions in active plasmon wave guides --- p.99 / Chapter 6.3 --- Routing and splitting of electromagnetic energy in nanosphere plasmon waveguides --- p.103 / Chapter 6.4 --- Conclusions --- p.107 / Chapter Chapter7 --- Conclusions and outlook --- p.109 / Appendix --- p.117 / Bibliography --- p.124