Symmetry plays a crucial role in exploring the laws of nature. By exploiting some of the underlying analogies between the mathematical formalism of quantum mechanics and that of electrodynamics, in this dissertation we show that optics can provide a fertile ground for studying, observing, and utilizing some of the peculiar symmetries that are currently out of reach in other areas of physics. In particular, in this work, we investigate two important classes of symmetries, parity-time symmetry (PT) and supersymmetry (SUSY), within the context of classical optics. The presence of PT symmetry can lead to entirely real spectra in non-Hermitian systems. In optics, PT-symmetric structures involving balanced regions of gain and loss exhibit intriguing properties which are otherwise unattainable in traditional Hermitian systems. We show that selective PT symmetry breaking offers a new method for achieving single mode operation in laser cavities. Other interesting phenomena also arise in connection with PT periodic structures. Along these lines, we introduce a new class of optical lattices, the so called mesh lattices. Such arrays provide an ideal platform for observing a range of PT-related phenomena. We show that defect sates and solitons exist in such periodic environments exhibiting unusual behavior. We also investigate the scattering properties of PT-symmetric particles and we show that such structures can deflect light in a controllable manner. In the second part of this dissertation, we introduce the concept of supersymmetric optics. In this regard, we show that any optical structure can be paired with a superpartner with similar guided wave and scattering properties. As a result, the guided mode spectra of these optical waveguide systems can be judiciously engineered so as to realize new families of mode filters and mode division multiplexers and demultiplexers. We also present the first experimental demonstration of light dynamics in SUSY ladders of photonic lattices. In addition a new type of transformation optics based on supersymmetry is also explored. Finally, using the SUSY formalism in non-Hermitian settings, we identify more general families of complex optical potentials with real spectra.

Non-reciprocal wave transmission is a phenomenon witnessed in certain photonic devices when the wave propagation dynamics through the device along one direction differs greatly from the dynamics along the counter-propagating direction. Specifically, it refers to significant power transfer occurring in one direction, and greatly reduced power transfer in the opposite direction. The resulting effect is to isolate the directionality of wave propagation, allowing transmission to occur along one direction only. Given the popularity of photonic integrated circuits (PIC), in which all the optical components are fabricated on the same chip so that the entire optical system can be made more compact, it is desirable to have an easily integrated optical isolator. Common free-space optical isolator designs, which rely on the Faraday effect, are limited by the availability of suitable magnetic materials. This research proposes a novel integrated optical isolator based on an array of closely spaced, identical waveguides. Because of the nonlinear optical properties of the material, this device exploits the differing behaviors of such an array when illuminated with either a high power or a low power beam to achieve non-reciprocal wave transmission in the forwards and backwards directions, respectively. The switching can be controlled electro-optically via an integrated gain section which provides optical amplification before the input to the array. The design, fabrication, characterization and testing of this optical isolator are covered in this dissertation. We study the switching dynamics of this device and present its optimum operating conditions.

For the past few decades, tremendous progress has been made on liquid crystal display (LCD) technologies in terms of stability, resolution, contrast ratio, and viewing angle. The remaining challenge is response time. The state-of-the-art response time of a nematic liquid crystal is a few milliseconds. Faster response time is desirable in order to reduce motion blur and to realize color sequential display using RGB LEDs, which triples the optical efficiency and resolution density. Polymer-stabilized blue phase liquid crystal (PS-BPLC) is a strong candidate for achieving fast response time because its self-assembled cubic structure greatly reduces the coherence length. The response time is typically in the submillisecond range and can even reach microsecond under optimized conditions. Moreover, it exhibit several attractive features, such as no need for surface alignment layer, intrinsic wide viewing angle, and cell gap insensitivity if an in-plane-switching (IPS) cell is employed. In this dissertation, recent progresses in polymer-stabilized blue phases, or more generally optically-isotropic liquid crystals, are presented. Potential applications in display and photonic devices are also demonstrated. In Chapter 1, a brief introduction of optically isotropic liquid crystals is given. In Chapter 2, we investigate each component of polymer-stabilized blue phase materials and provide guidelines for material preparation and optimization. In Chapter 3, the electro-optical properties of PS-BPLCs, including electric-field-induced birefringence and dynamic behaviors are characterized. Theoretical models are proposed to explain the physical phenomena. Good agreements between experimental data and models are obtained. The proposed models also provide useful guidelines for both material and device optimizations. Four display and photonic devices using PS-BPLCs are demonstrated in Chapter 4. First, by red-shifting the Bragg reflection and using circular polarizers, we reduce the LCD driving voltage by 35% as compared to a short-pitch BPLC while maintaining high contrast ratio and submillisecond response time. Second, a turning film which is critically needed for widening the viewing angle of a vertical field switching (VFS) BPLC mode is designed. With this film, the viewing angle of VFS is widened to [plus or minus] 80[degrees] in horizontal direction and [plus or minus] 50[degrees] in vertical direction. Without this turning film, the viewing angle is only [plus or minus]30[degrees], which is too narrow for most applications. Third, a reflective BPLC display with vivid colors, submillisecond response time, and natural grayscales is demonstrated for the first time. The proposed BPLC reflective display opens a new gateway for 3D reflective displays; it could make significant impact to display industry. Finally, we demonstrate a tunable phase grating with a high diffraction efficiency of 40% and submillisecond response time. This tunable grating exhibits great potential for photonic and display applications, such as optical interconnects, beam steering, and projection displays.

This thesis studies the center wavelength accuracy of a Fiber Bragg Grating Sensor system that has a large number of sensor elements both as a function of wavelength and as a function of position. Determining the center wavelength of each of the fiber optic sensors is a critical parameter that ultimately determines sensor accuracy. The high density environment can result in degradation of accuracy of the center wavelength measurement. This thesis aims to quantify this measurement error both with theoretical and experimental studies. There are many sensing applications where optical fiber sensors are preferred over electrical sensors, such as the oil and gas industry where fiber optic sensors are used to monitor wells and pipelines due to their low signal degradation over long distances and immunity to harsh physical environments. Fiber Bragg grating (FBG) sensors in particular have widespread use because of their versatility, measurement sensitivity, and distributed multiplexing abilities. In conventional wavelength multiplexing, up to 50 FBG sensors are spread out over a band of 100nm, each with a center wavelength difference large enough so that each element can be individually measured. However, numerous sensing applications require several hundred to over a thousand sensors cascaded together on a single fiber. These sensor arrays use a combination of WDM and TDM for measurements, where many FBG sensors with the same center wavelength are separated by a long enough length of fiber so that the reflected signals are separated in time. These Wavelength-to-Time Domain Multiplexing (W-TDM) measurements are enabled by Insight Photonic’s new ‘akinetically’ swept, all-semiconductor laser. This laser is a Vernier-Tuned Distributed Bragg Reflector (VT-DBR) device, capable of rapidly sweeping through different wavelengths without any moving parts. Attributes that make this laser superior to mechanically-swept lasers include: 1) short and long term consistent sweep-sweep reliability, 2) availability at many wavelengths, 3) a narrow linewidth with single longitudinal mode, and 4) the ability to do non-traditional sweep patterns that facilitate measurement of high-density sensor networks. In this thesis, experiments will be performed in the lab with the Insight VT-DBR laser to determine how accurately the center wavelength of a single Fiber Bragg grating can be measured. Experiments will also be performed with two and three FBGs to compare different algorithmic approaches to measurements. The second part of the thesis will simulate both single and multiple FBG sensor environments, comparing the center wavelength measurement accuracy results for different parameters including signal-to-noise ratios, wavelength point density, FBG loss and width, and multiple algorithmic approaches. The results of these experiments and simulations will demonstrate how accurate a FBG sensor system is at particular parameters, which will be useful to those designing a sensor network or performing similar experiments.

<p>The rapid development of fiber optic communication systems requires higher transmission data rate and longer reach. This thesis deals with the limiting factors in design of long-haul fiber optic communication systems and the techniques used to suppress their resulting impairments. These impairments include fiber chromatic dispersion, the Ker nonlinearity and nonlinear phase noise due to amplified spontaneous emission.</p> <p>In the first part of this thesis, we investigate the effect of amplified spontaneous noise in quasi-linear systems. In quasi-linear systems, inline optical amplifiers change the amplitude of the optical field envelope randomly and fiber nonlinear effects such as self phase modulation (SPM) convert the amplitude fluctuations to phase fluctuations which is known as nonlinear phase noise. For M-ary phase shift keying (PSK) signals, symbol error probability is determined solely by the probability density function (PDF) of the phase. Under the Gaussian PDF assumption, the phase variance can be related to the symbol error probability for PSK signals. We implemented the simulation based on analytical phase noise variance and Monte-Carlo simulation, and it is found that the analytical approximation is in good agreement with numerical simulations. We have developed analytical expressions for the linear and nonlinear phase noise variance due to SPM using second-order perturbation theory. It is found that as the transmission reach and/or lunch power increase, the variance of the phase noise calculated using first order perturbation theory becomes inaccurate. However, the variance calculated using second order perturbation theory is in good agreement with numerical simulations. We have also showed that the analytical formula given in this chapter for the variance of nonlinear phase noise can be used as a design tool to investigate the optimum system design parameters such as average power and dispersion maps for coherent fiber optic systems based on phase shift keying due to the fact that the numerical simulation of nonlinear Schrodinger (NLS) equation is time consuming, however, the analytical method based on solving NLS equation using perturbation approximation is quite efficient and therefore the analytical variance can be obtained more easily without requiring extensive computational efforts, and also with fairly good accuracy.</p> <p>In the second part of this thesis, an improved optical signal processing using highly nonlinear fibers is studied. This technique, optical backward propagation (OBP), can compensate for the fiber dispersion and nonlinearity using optical nonlinearity compensators (NLC) and dispersion compensating fibers (DCF), respectively. In contrast, digital backward propagation (DBP) uses the high-speed digital signal processing (DSP) unit to compensate for the fiber nonlinearity and dispersion digital domain. NLC imparts a phase shift that is equal in magnitude to the nonlinear phase shift due to Fiber propagation, but opposite in sign. In principle, BP schemes could undo the deterministic (bit-pattern dependent) nonlinear impairments, but it can not compensate for the stochastic nonlinear impairments such as nonlinear phase noise. We also introduced a novel inline optical nonlinearity compensation (IONC) technique. Our Numerical simulations show that the transmission performance can be greatly improved using OBP and IONC. Using IONC, the transmission reach becomes almost twice of DBP. The advantage of OBP and IONC over DBP are as follows: OBP/IONC can compensate the nonlinear impairments for all the channels of a wavelength division multiplexed system (WDM) in real time while it would be very challenging to implement DBP for such systems due to its computational cost and bandwidth requirement. OBP and IONC can be used for direct detection systems as well as for coherent detection while they provide the compensation of dispersion and nonlinearity in real time, but DBP works only for coherent detection and currently limited to off-line signal processing.</p> / Master of Applied Science (MASc)

<p>A new model, referred to as the Rational Dispersion Model is proposed for modeling of dispersive materials in wide wavelength range using the Finite-Difference Time-Domain(FDTD) method. A hardware-accelerated FDTD method combined with the matrix pencil method is proposed to solve both guided and leaky modes. A circuit model based on the complex mode theory is proposed for analysis of large scale structures with non-negligible radiation effects.</p> / Doctor of Philosophy (PhD)

<p>Optical waveguide is a very important component in numerous optical structures, devices and photonic circuits. With the rapid development of fabrication technologies, increasing integrated complexity and different materials characteristics, there is higher demand on high-index contrast waveguide with arbitrary cross section and anisotropic material, which indicates the need to develop an efficient, high-performance mode solver to analyze optical waveguides to reduce the fabrication cycle and total cost. Modeling and simulation methods, including Finite Difference Time-Domain (FDTD) method, Finite Element Method (FEM), Beam Propagating Method (BPM), Mode Matching Method (MMM) and Couple Mode Theory (CMT), etc, have been popular for years. Among those methods, FEM is a good and efficient method, especially for its superiority on arbitrary meshes.</p> <p>In this thesis, both scalar and vectorial FEM mode solvers are implemented with an emphasis on dealing with the radiation and evanescent modes by enclosing the whole region with the Perfect Matched Layer (PML) and Perfect Reflecting Boundary (PRB). Thus, the unbounded and continuous radiation modes together with evanescent modes are replaced by what we called "complex modes", but still keeping the completeness and orthogonality properties.</p> / Master of Applied Science (MASc)

published_or_final_version / abstract / Electrical and Electronic Engineering / Master / Master of Philosophy

No description available.

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