La nanophotonique non-linéaire offre une opportunité unique pour ouvrir de nouvelles voies vers des applications dans les détecteurs, les ordinateurs et la cryptographie quantique. Cependant, la faiblesse intrinsèque de la réponse non-linéaire des milieux de taille inférieure au micromètres limite fortement l’efficacité des sources optique à cette échelle. Combiner l'exaltation du champ électromagnétique dans les métaux (appelée résonance plasmonique) et l'efficacité non-linéaire de nanocristaux non-centosymétriques apparait extrêmement souhaitable et constitue le cœur de ce projet. Dans ce cadre, le travail présenté dans cette thèse consiste en une approche numérique quantitative des processus linéaires et non-linéaires (génération de second harmonique et de paires de photons) mis en jeu dans les nanostructures hybrides afin de pouvoir « accorder » les résonances plasmoniques et optimiser le couplage lumière-matière. L’étude menée prédit une exaltation par plusieurs ordres de grandeur des processus non linéaires modélisés au sein de particules composites. / Nonlinear nanophotonics offers a unique opportunity to open new path toward a wide range of pratical applications in sensors, quantum computers, cryptography devices. The main challenge is to enhance nonlinear response of nanosized particles in order to integrate them in optical components. On this purpose, we want to combine the electromagnetic field enhancement in metals (due to a phenomenon called plasmonic resonances) with non linear efficiency of non centrosymmetric nanocrystals.In this thesis, we present a numerical approach for simulating linear and non linear optical processes (second harmonic generation and spontaneous numerical down conversion) in hybrid nanostructures in order to “ tune “ plasmonic resonances and optimize light/matter coupling. The study predicts an enhancement by several orders of magnitude of the non linear phenomena modeled in composite nano particles.

Optical detection devices such as optical biosensors and optical spectrometers are widely used in many applications for the functions of measurements, inspections and analysis. Due to the large dimension of prisms and gratings, the traditional optical devices normally occupy a large space with complicated components. Since cheaper and smaller optical devices are always in demand, miniaturization has been kept going for years. Thanks to recent fabrication advances, nanophotonic devices such as semiconductor laser chips have been growing in number and diversity. However, the optical biosensor chips and the optical spectrometer chips are seldom reported in the literature. For the reason of improving system integration, the study of ultra-compact, low-cost, high-performance and easy-alignment optical biosensors and optical spectrometers are imperative. This thesis is an endeavor in these two subjects and will present our research work on studying the optical transmission properties of dielectric aperture arrays and developing new optical biosensors and optical spectrometers. / Subsequently, optical transmission properties through a self-mixing interferometer array are studied and a novel high-resolution cost-effective optical spectrometer is proposed. The miniature interferometer-based spectrometer is made of polymethyl methacrylate (PMMA) with a CCD as the detector. The detected intensity of each CCD pixels contains the spectral information. Since each frequency component in the incoming beam corresponds to a unique phase difference of the two beam portions of each optical interferometer, the total intensity received by each CCD pixel, which is resulted from the addition of the interference signals from all the frequency components in the beam, should also be unique. Therefore, the spectrum calculation is a problem to solve an ill-posed linear system by using Tikhonov regularization method. Simulation results show that the resolution can reach picometer level. Apart from the choice of path difference between the interfering beams, the spectral resolution also depends on the signal-to-noise ratio and analogue-digital conversion resolution (dynamic range) of the CCD chip. In addition, the theory of uniform waveguide scattering is explored to expand the possibility of using such mini-interferometers for performing free-space spectral analysis of waveguide devices. At the same time, the method of least squares is used to correct the pixel non-uniformity of the CCD so as to improve the performance of the spectrometer. / The first half of the thesis demonstrates that the optical phase shift associated with the surface plasmon (SP) assisted extraordinary optical transmission (EOT) in nano-hole arrays fabricated in a metal film has a strong dependence on the material refractive index value in close proximity to the holes. A novel refractive index sensor based on detecting the EOT phase shift is proposed by building a model. This device readily provides a 2-D biosensor array platform for non-labeled real-time detection of a variety of organic and biological molecules in a sensor chip format, which leads to a high packing density, minimal analyte volumes, and a large number of parallel channels while facilitating high resolution imaging and supporting a large space-bandwidth product (SBP). Simulation (FDTD Solutions, Lumerical Solutions Inc) results indicate an achievable sensitivity limit of 4.37x10-9 refractive index units (RIU) and a dynamic range as large as 0.17 RIU. / The sensor chip and spectrometer chip introduced here are based on the interference of light transmitted through dielectric aperture arrays. Their compact feature renders these devices ideal for miniaturization and integration as the systems in microfluidics architectures and lab-on-chip designs. / Yang, Tao. / Adviser: H. P. Ho. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 150-163). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

This dissertation comprises experimental studies on the synthesis and applications of metallic nanoshells. These are a class of nanoparticles composed of a dielectric core and a thin metallic shell. Metallic nanoshells play an important role in nanotechnology, particularly in nanomedicine, due to their peculiar optical properties. The overall objectives of the dissertation were to improve the fabrication of these nanoparticles, and to demonstrate new applications of these materials in cancer research and spectroscopy. The fabrication of nanoshells is a multi-step process. Previously to our work, the procedures for the synthesis of nanoshells reported in the literature lacked systematic characterization of the various steps. The procedure was extremely time-consuming and the results demonstrated a high degree of size variation. In Chapter 3, we have developed characterization tools that provide checkpoints for each step of the synthesis. We demonstrated that it is possible to control the degree of coverage on the shell for a fixed amount of reagents, and also showed important differences on the shell growth phase for gold and silver. The synthetic optimization presented in Chapter 3 led to an overall faster protocol than those previously reported. Although the improvements presented in Chapter 3 led to a higher degree of control on the synthesis of nanoshells, the variations in the resulting particle population were still too large for applications in single particle spectroscopy and imaging. In Chapter 4, the synthesis was completely reformulated, aiming to narrow the size distribution of the nanoshell colloids. Through the use of a reverse microemulsion, we were able to fabricate ultramonodisperse silica (SiO2) cores, which translate into nanoshell colloids with narrow extinction bands that are comparable to those of a single nanoshell. We then fabricate a library of colloids with different core sizes, shell thicknesses and composition (gold or silver). The localized surface plasmon resonance (LSPR) of these colloids span across the visible range. From this library, two nanoshells (18nm silver on a 50nm SiO2 core, and 18nm gold on a 72nm SiO2 core) were selected for a proof of principle cell imaging experiment. The silver nanoshells were coated with a nuclear localization signal, allowing it to target the nuclear membrane. The gold nanoshells were coated with an antibody that binds to a receptor on the plasma membrane of MCF-7 human breast cancer cells. The nanoshells were easily distinguishable by eye in a dark field microscope and successful targeting was demonstrated by hyperspectral dark field microscopy. A comparison was made between fluorescent phalloidin and nanoshells, showing the superior photostability of the nanoparticles for long-term cell imaging. The results from Chapter 4 suggest that the nanoshells obtained by our new synthetic route present acceptable particle-to-particle variations in their optical properties that enables single particle extinction spectroscopy for cell imaging. In Chapter 5 we explored the use of these nanoshells for single-particle Surface-enhanced Raman spectroscopy (SERS). Notice that particle-to-particle variations in SERS are expected to be more significant than in extinction spectroscopy. This is because particle-to-particle SERS variabilities are driven by subtle changes in geometric parameters (particle size, shape, roughness). Two types of gold nanoshells were prepared and different excitation wavelengths (λex) were evaluated, respective to the LSPR of the nanoshells. Individual scattering spectra were acquired for each particle, for a total of 163 nanoshells, at two laser excitation wavelengths (632.8 nm and 785 nm). The particle-to-particle variations in SERS intensity were evaluated and correlated to the efficiency of the scattering at the LSPR peak. Chapter 6 finally shows the application of gold nanoshells as a platform for the direct visualization of circulating tumor cells (CTCs). 4T1 breast cancer cells were transduced with a non-native target protein (Thy1.1) and an anti-Thy1.1 antibody was conjugated to gold nanoshells. The use of a transduced target creates the ideal scenario for the assessment of nonspecific binding. On the in vitro phase of the study, non-transduced cells were used as a negative control. In this phase, parameters such as incubation times and nanoshell concentration were established. A murine model was then developed with the transduced 4T1 cells for the ex vivo portion of the work. Non-transduced cells were implanted in a control group. Blood was drawn from mice in both groups over the course of 29 days. Antibody-conjugated nanoshells were incubated with the blood samples and detection of single CTCs was achieved in a dark field microscope. Low levels of nonspecific binding were observed in the control group for non-transduced cells and across different cell types normally found in peripheral blood (e.g. lymphocytes). All positive and negative subjects were successfully identified. Chapter 7 provides an outlook of the work presented here and elaborates on possible directions to further develop the use of nanoshells in bioapplications and spectroscopy. / Graduate / 2019-05-03

Através da modificação adequada da superfície de nanopartículas de ouro com uma molécula sulfurada que apresenta vários sítios de coordenação, foi possível desenvolver um conceito interessante de sensoriamento quantitativo conjugado ao efeito SERS. Estudos com sistemas desse tipo permitem explicar não apenas como uma molécula se liga a uma superfície, mas também como aproveitar essas informações para elaborar sensores de alta sensibilidade. Entretanto, as teorias eletrodinâmico-quânticas que regem as interações dos plasmons de superfície ainda estão sendo trabalhadas. Dessa forma, o presente trabalho procura explorar as teorias atuais sobre a origem dos plasmons e as interações plasmônicas entre as partículas. Essas interações promovem fenômenos de intensificação do espalhamento Raman por superfície e também foram discutidas. Visando conhecer e compreender os fenômenos envolvidos, foram sintetizadas nanopartículas de ouro estabilizadas com 2,4,6-trimercapto-1,3,5-triazina e estudada a química do ligante na superfície das nanopartículas de ouro. Além disso, foi estudada a influência dos equilíbrios ácido-base nos espectros SERS e monitorou-se as bandas mais diretamente sensíveis ao pH, associando as mudanças observadas aos diversos equilíbrios das espécies presentes em solução. Por fim, explorou-se o conceito de sensoriamento através das mudanças nos modos vibracionais dos espectros SERS, na formação de complexos em superfície. / Surface modification of gold nanoparticles with a molecule exhibiting several coordination points, allowed to elaborate an interesting concept for quantitative sensing conjugated with the SERS effect. In such systems it is important to know how the molecule binds to the surface, since, based on those informations one can elaborate sensors displaying high sensibility.. However, in dealing with the interaction of nanoparticles with light, the electrodynamic-quantum theories related to the interactions of the surface plasmons are not yet completely developed. In this way, in this t dissertation we made use of the current theories to understand the origin of the plasmons and of how they interact with the the nanoparticles. We have synthesized gold nanoparticles stabilized with 2,4,6-trimercapto-1,3,5-triazine and studied the ligand chemistry at the particles surface.. The influence of acid-base equilibria was studied based on the changes of the SERS spectra SERS with the pH, and interpreted in terms of the several equilibria of the species in solution. Finally, a new sensing concept, based on the observed changes in the SERS spectra in the presence of metal ions, was successfully demonstrated.

abstract: Proteins play a central role to human body and biological activities. As powerful tools for protein detections, many surface plasmon resonance based techniques have been developed to enhance the sensitivity. However, sensitivity is not the only final goal. As a biosensor, four things really matter: sensitivity, specificity, resolution (temporal/spatial) and throughput. This dissertation presents several works on developing novel plasmonic based techniques for protein detections on the last two aspects to extend the application field. A fast electrochemically controlled plasmonic detection technique is first developed with the capability of monitoring electrochemical signal with nanosecond response time. The study reveals that the conformational gating of electron transfer in a redox protein (cytochrome c) takes place over a broad range of time scales (sub-µs to ms). The second platform integrates ultra-low volume piezoelectric liquid dispensing and plasmonic imaging detection to monitor different protein binding processes simultaneously with low sample cost. Experiment demonstrates the system can observe binding kinetics in 10×10 microarray of 6 nL droplet, with variations of kinetic rate constants among spots less than ±5%. A focused plasmonic imaging system with bi-cell algorithm is also proposed for spatial resolution enhancement. The two operation modes, scanning mode and focus mode, can be applied for different purposes. Measurement of bacterial aggregation demonstrates the higher spatial resolution. Detections of polystyrene beads binding and 50 nm gold nanoparticles oscillation show a high signal to noise ratio of the system. The real properties of protein rely on its dynamic personalities. The above works shed light upon fast and high throughput detection of protein kinetics, and enable more applications for plasmonic imaging techniques. It is anticipated that such methods will help to invoke a new surge to unveil the mysteries of biological activities and chemical process. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2018

Luk, Wai Chun = / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 101-108). / Abstracts in English and Chinese. / Luk, Wai Chun = / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Theoretical Background --- p.5 / Chapter 2.1 --- Maxwell´ةs equations in matter --- p.5 / Chapter 2.2 --- Dielectric constant of materials --- p.8 / Chapter 2.3 --- Dispersion relation of surface plasmon polaritons --- p.10 / Chapter 2.4 --- Excitation of surface plasmon polaritons --- p.16 / Chapter 2.4.1 --- Prism coupling --- p.17 / Chapter 2.4.2 --- Grating coupling --- p.21 / Chapter 2.5 --- Diffraction of light in gratings --- p.26 / Chapter 2.6 --- Applications --- p.27 / Chapter 3 --- Analysis Methods --- p.29 / Experimental Section --- p.29 / Chapter 3.1 --- Interference Lithography --- p.29 / Chapter 3.2 --- Gold grating fabrication --- p.32 / Chapter 3.2.1 --- Substrate preparation --- p.33 / Chapter 3.2.2 --- Photoresist preparation --- p.34 / Chapter 3.2.3 --- Spin coating of omnicoat and photoresist --- p.35 / Chapter 3.2.4 --- Interference lithography set-up and procedures --- p.35 / Chapter 3.2.5 --- The post-exposed treatments --- p.37 / Chapter 3.2.6 --- The optimal exposure time calibration --- p.37 / Chapter 3.2.7 --- Gold thin film deposition --- p.39 / Chapter 3.2.8 --- Typical gold grating sample --- p.41 / Chapter 3.3 --- Measurement system --- p.41 / Chapter 3.3.1 --- The angle dependent reflectivity measurement --- p.42 / Chapter 3.3.2 --- Data presentation of a typical band structure --- p.45 / Chapter 3.3.3 --- Periodicity measurement of the grating samples --- p.48 / Chapter 3.3.4 --- Diffracted intensity measurement of gratings --- p.52 / Chapter 3.3.5 --- Data presentation of the angle dependent diffracted intensity measurement --- p.53 / Calculation Section --- p.54 / Chapter 3.4 --- RCWA simulations --- p.54 / Chapter 3.4.1 --- The dispersion relation --- p.56 / Chapter 3.4.2 --- The diffracted intensity --- p.56 / Chapter 3.4.3 --- The field pattern graphs --- p.57 / Chapter 4 --- Resonance modes in one-dimensional gold gratings --- p.60 / Chapter 4.1 --- Structure of the gold grating samples --- p.61 / Chapter 4.2 --- Results of angle dependent reflectivity --- p.63 / Chapter 4.2.1 --- Surface Plasmon Polaritons (SPPs) --- p.65 / Chapter 4.2.2 --- Wood´ةs anomaly --- p.65 / Chapter 4.2.3 --- Waveguide Resonance (WG) --- p.67 / Chapter 4.2.4 --- Coupling of SPPs and WG --- p.67 / Chapter 4.3 --- Results of angle dependent diffracted intensity measurement --- p.68 / Chapter 4.4 --- Basic properties of SPPs and WG modes by RCWA --- p.73 / Chapter 4.4.1 --- Sample 1 (D = 40 nm) --- p.74 / Chapter 4.4.1(a) --- λ = 980 nm of Sample 1 --- p.75 / Chapter 4.4.1(b) --- λ = 633 nm of Sample 1 --- p.81 / Chapter 4.4.2 --- Sample 2 (D = 390 nm) --- p.83 / Chapter 4.4.2(a) --- λ = 980 nm of Sample 2 --- p.85 / Chapter 4.4.2(b) --- λ = 725 nm of Sample 2 --- p.87 / Chapter 4.4.2(c) --- λ = 633 nm of Sample 2 --- p.92 / Chapter 4.5 --- Summary --- p.97 / Chapter 5 --- Conclusions --- p.99 / Bibliography --- p.101

Sham, Chun Hong = 金屬光栅光學特性的實驗和理論研究 / 沈鎮康. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 109-111). / Abstract also in Chinese. / Sham, Chun Hong = Jin shu guang shan guang xue te xing de shi yan he li lun yan jiu / Shen Zhenkang. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Overview of the Thesis --- p.2 / Chapter 2 --- Basic Theory --- p.4 / Chapter 2.1 --- Dielectric Constant of Metals --- p.5 / Chapter 2.2 --- The Maxwell´ةs Equations --- p.7 / Chapter 2.3 --- Scaling Properties of the Maxwell´ةs Equations --- p.9 / Chapter 2.4 --- Translational Symmetry and the Bloch´ةs Theorem --- p.10 / Chapter 2.4.1 --- Continuous Translational Symmetry --- p.11 / Chapter 2.4.2 --- Discrete Translational Symmetry --- p.12 / Chapter 2.4.3 --- Photonic Bloch´ةs Theorem --- p.13 / Chapter 3 --- Principles of Rigorous Coupled Wave Analysis --- p.14 / Chapter 3.1 --- Mathematical Formulation --- p.15 / Chapter 3.2 --- One-layer systems --- p.15 / Chapter 3.3 --- Layered Systems --- p.19 / Chapter 3.3.1 --- Matching Boundary Conditions --- p.19 / Chapter 3.3.2 --- The Transfer Matrices --- p.21 / Chapter 3.3.3 --- Scattering Matrices --- p.22 / Chapter 3.4 --- Calculation of Reflection and Transmission --- p.24 / Chapter 3.5 --- Calculation of Field Pattern --- p.26 / Chapter 3.5.1 --- Finding the Coefficients --- p.26 / Chapter 3.5.2 --- Summing to Get the Field --- p.27 / Chapter 3.6 --- 5-polarization --- p.27 / Chapter 3.7 --- Analogy to mechanics --- p.29 / Chapter 3.8 --- Conclusion --- p.30 / Chapter 4 --- Numerical Implementation of Rigorous Coupled Wave Analysis --- p.31 / Chapter 4.1 --- Finite Number of Terms --- p.31 / Chapter 4.2 --- Fourier Factorization Rule --- p.32 / Chapter 4.3 --- Calculation of Field Pattern --- p.34 / Chapter 4.4 --- Transfer Matrix for Forward Deduction --- p.36 / Chapter 4.5 --- Calculation of Time-Averaged Poynting Vector --- p.36 / Chapter 4.6 --- Convergence of RCWA --- p.37 / Chapter 4.7 --- Simple Examples --- p.40 / Chapter 4.7.1 --- Oblique Incidence on Vacuum --- p.40 / Chapter 4.7.2 --- Oblique Incidence on Semi-Infinite Glass --- p.41 / Chapter 4.7.3 --- Normal Incidence on a Thin Gold Film --- p.41 / Chapter 5 --- A Tunable All-Direction Light Absorber --- p.43 / Chapter 5.1 --- Description of the Absorber --- p.44 / Chapter 5.2 --- Tunability --- p.45 / Chapter 5.3 --- Theoretical Understanding on the Results --- p.46 / Chapter 5.4 --- Other EM modes Involved --- p.49 / Chapter 5.5 --- Structural Flexibility --- p.54 / Chapter 6 --- Sample Preparation Techniques --- p.57 / Chapter 6.1 --- Interference Lithography --- p.57 / Chapter 6.1.1 --- Basic Principle of IL --- p.58 / Chapter 6.1.2 --- Experimental Setup for IL --- p.59 / Chapter 6.1.3 --- Experimental Procedures for IL --- p.60 / Chapter 6.1.4 --- Tuning the Period --- p.61 / Chapter 6.1.5 --- Tuning Grating Width --- p.62 / Chapter 6.1.6 --- Tuning the grating height --- p.64 / Chapter 6.2 --- Sputtering --- p.65 / Chapter 6.2.1 --- Description of Sputtering System --- p.65 / Chapter 6.2.2 --- Effect of Varying the Position on Sample Holder --- p.66 / Chapter 6.3 --- Chemical deposition of silver --- p.69 / Chapter 7 --- Sample Characterization Techniques --- p.72 / Chapter 7.1 --- Scanning Electron Microscope --- p.72 / Chapter 7.1.1 --- Grating width measurement --- p.72 / Chapter 7.1.2 --- Sidewall Coverage Measurement --- p.73 / Chapter 7.2 --- Thickness Measurement --- p.74 / Chapter 7.3 --- Reflectance Measurement --- p.75 / Chapter 7.3.1 --- Experimental Setup --- p.76 / Chapter 7.3.2 --- Use of Prism --- p.79 / Chapter 8 --- Experimental Realization of All-Direction Light Absorber --- p.82 / Chapter 8.1 --- Reflectance of Glass Substrate --- p.82 / Chapter 8.2 --- Planar Metal-SU8-Metal Systems --- p.87 / Chapter 8.3 --- SU8 Grating on Glass Substrate --- p.89 / Chapter 8.4 --- SU8 Grating on Gold Substrate --- p.92 / Chapter 8.4.1 --- Grating on a Thick Layer of Gold --- p.93 / Chapter 8.4.2 --- Grating on a Thin Layer of Gold --- p.93 / Chapter 8.5 --- Cavities-Embedded Systems and Future Work --- p.96 / Chapter 8.6 --- Summary and Future Experimental Work --- p.100 / Chapter 9 --- Conclusion --- p.102 / Chapter A --- Notes on Glass Cleaning --- p.104 / Chapter B --- An Experiment on Sidewall Coverage --- p.107 / Bibliography --- p.109

Através da modificação adequada da superfície de nanopartículas de ouro com uma molécula sulfurada que apresenta vários sítios de coordenação, foi possível desenvolver um conceito interessante de sensoriamento quantitativo conjugado ao efeito SERS. Estudos com sistemas desse tipo permitem explicar não apenas como uma molécula se liga a uma superfície, mas também como aproveitar essas informações para elaborar sensores de alta sensibilidade. Entretanto, as teorias eletrodinâmico-quânticas que regem as interações dos plasmons de superfície ainda estão sendo trabalhadas. Dessa forma, o presente trabalho procura explorar as teorias atuais sobre a origem dos plasmons e as interações plasmônicas entre as partículas. Essas interações promovem fenômenos de intensificação do espalhamento Raman por superfície e também foram discutidas. Visando conhecer e compreender os fenômenos envolvidos, foram sintetizadas nanopartículas de ouro estabilizadas com 2,4,6-trimercapto-1,3,5-triazina e estudada a química do ligante na superfície das nanopartículas de ouro. Além disso, foi estudada a influência dos equilíbrios ácido-base nos espectros SERS e monitorou-se as bandas mais diretamente sensíveis ao pH, associando as mudanças observadas aos diversos equilíbrios das espécies presentes em solução. Por fim, explorou-se o conceito de sensoriamento através das mudanças nos modos vibracionais dos espectros SERS, na formação de complexos em superfície. / Surface modification of gold nanoparticles with a molecule exhibiting several coordination points, allowed to elaborate an interesting concept for quantitative sensing conjugated with the SERS effect. In such systems it is important to know how the molecule binds to the surface, since, based on those informations one can elaborate sensors displaying high sensibility.. However, in dealing with the interaction of nanoparticles with light, the electrodynamic-quantum theories related to the interactions of the surface plasmons are not yet completely developed. In this way, in this t dissertation we made use of the current theories to understand the origin of the plasmons and of how they interact with the the nanoparticles. We have synthesized gold nanoparticles stabilized with 2,4,6-trimercapto-1,3,5-triazine and studied the ligand chemistry at the particles surface.. The influence of acid-base equilibria was studied based on the changes of the SERS spectra SERS with the pH, and interpreted in terms of the several equilibria of the species in solution. Finally, a new sensing concept, based on the observed changes in the SERS spectra in the presence of metal ions, was successfully demonstrated.

Nanostructures have received much attention from the physical and engineering communities in the past few years. The understanding of the behavior of nanostructures in various conditions is warranted since the applications of such materials in optics, electronics, and mechanics is ever expanding. This thesis investigates a specific type of structure, a concentric cylindrical. More specifically, the dispersion relation of radiating and non-radiating plasmon polaritons (quasi-particles resulting from interactions of photons and surface electrons) is studied under varying conditions. We intend to show the influence of changing the thickness of the layers, the number of layers, the curvature of each layer, and the type of material the layers has on the dispersion relation. By first solving Maxwell's equations in cylindrical coordinates and applying boundary conditions, we developed a matrix equation through which we were able to obtain the dispersion relation for an N layered cylindrical system characterized by a specified dielectric function placed into a background. For the non-radiative modes we used the bisection method to obtain the dispersion relation; however, since radiative modes encompass virtual modes, which contain real and imaginary components, a Newton method was used to gather that data. The dielectric functions for silver and carbon dielectric functions were used to describe the material layers within the radiative and non-radiative regimes. The results show that curvature changes influence the surface plasmon polariton dispersion by either red shifting or blue shifting the energetics. Lifetimes and damping are seen to be influenced by the curvature as well. The addition of more layers to the system results in an increase in the complexity of the dispersion energetics. The results obtained would help provide better scanning tips within the optical microscopy field. Also, these results can have direct application to the field of photonics. Finally, these results also help provide the foundations to understanding the fundamentals of long-ranged forces in cylindrical layered structures.

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