When nanoparticles are small in size compared to the wavelength of incident light, a localized surface plasmon resonance occurs. For certain noble metals, such as gold and silver, this frequency occurs in the visible or near IR range, and therefore it can be utilized for many important applications. Only silver and gold nanoparticles were utilized in this thesis work, and they were used in application for three separate files: environment, catalysis, and energy.

<p>Antithrombin (AT) is one of the most important anticoagulant factors in the blood, and its effects are increased by the interaction with glycosaminoglycans, especially heparin. AT appears in two additional variants, other than the native form, and those variants have antiangiogenic properties and also bind to heparin. AT is found in two distinct isoforms (alfa, beta) where the difference lie in the degree of glycosylation. This project has shown interesting results regarding the dependence of calcium ions on the binding between heparin and antithrombin. The results show that the beta-isoform increases its affinity for heparin in the presence of calcium in contrast to the alfa-isoform, which shows a decrease in the heparin affinity under the same conditions. This project has also given results that after further investigation and development could be used for an improved set-up of the immobilisation of AT variants in a surface plasmon resonance system. The results show that immobilisation of a protein in the reference channel gives a better shielding effect between the negatively charged heparin molecules and the negatively charged dextran matrix. Furthermore a more significant difference was seen between the two heparin moieties used during binding affinity studies, especially for native AT.</p>

Les processus non-linéaires optiques à l'échelle nanométrique ont des rendements très faibles. Ainsi les structures métalliques permettant de confiner les champs électromagnétiques sur des zones sub-longueur d'onde sont intensivement étudiées.<br />Ce mémoire présente l'étude des propriétés optiques à l'échelle nanométrique de films granulaires métalliques. Les modes de résonances plasmons, quand ils sont excités, génèrent des pics d'exaltation localisés.<br />Pour faire les études expérimentales de ces échantillons, nous avons choisi la microscopie optique de champ proche à ouverture (SNOM). Nos résultats montrent la localisation de champs intenses dans des zones nanométriques. Ces exaltations dépendent de la longueur d'onde et de la polarisation. Il existe un régime purement diffusif quand les résonances plasmons ne sont pas excitées. En augmentant la longueur d'onde, les exaltations apparaissent, mais la diffusion est toujours présente. Une étude statistique par la fonction d'autocorrélation analyse ces deux régimes.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 198-210).

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 164-178).

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 243-262).

Broad spectral tunability is a desired feature of many photonic and plasmonic components, such as optical filters, semiconductor lasers, and plasmonic materials. Here I show that unique properties of long-range surface plasmon polaritons (LR SPP) allow one to produce optical components with very wide tuning range using small variations in the refractive index of the dielectric cladding material. As a proof-of-concept demonstration, I present operation of LR-SPP-based bandpass optical filters in which a 0.004 variation in the refractive index of the cladding dielectric translates into 210 nm of bandpass tuning at telecom wavelengths. The tuning mechanism proposed here may be used to create monolithic bandpass filters with tuning range spanning over more than an optical octave, compact and widely-tunable diode and quantum cascade laser systems, multi-spectral imagers, and other plasmonic components with broadly-tunable optical response. / text

The problem of heavy material and radiative losses in plasmonic devices has held back their implementation for compact and high-speed data storage and interconnects. One of the most interesting solutions to this problem currently under exploration is the addition of a gain material in close proximity to the metallic nanostructures for loss compensation. Here the physics of light transport in a nanoparticle array, and the operation of gain media in contact with the structure, are described and analytically modeled. A two-dimensional array of closely spaced gold nanoparticles has been fabricated by focused ion beam milling, and its electromagnetic response in the presence or absence of a dye coating has been simulated in preparation for pump-probe optical testing. The compensation of losses via a fluorophore coating has been proven for the first time in this geometry, for a physically realized sample. / text

Optical molecular imaging has burgeoned into a major field within biomedicine, and technologies that incorporate surface plasmon resonance effects have become a major focus within this field. Plasmon resonance has been defined as the collective oscillation of the conduction band electrons in certain metals (such as gold) in response to an electric field, such as an impinging wave of light. We show that elastic light scattering due to the plasmon resonance of nanometer-sized gold particles makes them powerful tools for optical imaging of epidermal growth factor receptor (EGFR) expression -- a major biomarker for carcinogenesis. Optical technologies in general are poised as cheap, flexible ways to aid in diagnosis and treatment of disease. In addition to supplying a bright, stable optical scattering signal and a convenient conjugation platform for targeting molecules, these materials display a unique behavior termed "plasmon coupling". This term refers to the dramatic optical property changes brought about by the presence of other nearby nanoparticles. These changes include a dramatic red-shifting in their peak plasmon resonance wavelength, as well as a non-linear, per-particle increase in the overall scattered power. We show that such conditions exist in cells and are primarily due to intricate protein trafficking mechanisms as part of the EGFR life-cycle. The observed variations in plasmon coupling can give clues as to the nanoscale organization of these important proteins. In addition, the resulting optical property changes result in a large, molecular-specific contrast enhancement due to the shifting of the resonance closer to the near infrared region, where biological tissues tend to be most transparent. Despite this enhancement, however, many tissues contain large endogenous signals, as well as barriers to delivery of both light and the nanoparticles. As such, we also show an example of a multifaceted approach for further increasing the apparent molecular-specific optical signals in imaging of EGFR expression by using an oscillating magnetic field. This serves to encode the signal from magnetically susceptible plasmonic nanoparticles, making their extraction from the background possible. Overall, the studies presented in this dissertation should serve to stimulate further investigations into a wide variety of technologies, techniques, and applications.

Coated nanoparticles (CNP) are core-shell particles consisting of differing layers of epsilon positive (EP) and epsilon negative (ENG) materials. The juxtaposition of these EP and ENG materials can lead to the possibility of coupling incident plane waves to surface plasmon resonances (SPR) for particles even highly subwavelength in size. We introduce standard models of the permittivities of the noble metals used in these CNPs, and propose corrections to them based on experimental data when their sizes are extremely small. Mie theory is the solution to plane wave scattering by spheres and we extend the solution here to spheres consisting of an arbitrary number of layers. We discuss the resonance behaviors of passive CNPs with an emphasis on how the Coated nanoparticles (CNP) are core-shell particles consisting of differing layers of epsilon positive (EP) and epsilon negative (ENG) materials. The juxtaposition of these EP and ENG materials can lead to the possibility of coupling incident plane waves to surface plasmon resonances (SPR) for particles even highly subwavelength in size. We introduce standard models of the permittivities of the noble metals used in these CNPs, and propose corrections to them based on experimental data when their sizes are extremely small. Mie theory is the solution to plane wave scattering by spheres and we extend the solution here to spheres consisting of an arbitrary number of layers. We discuss the resonance behaviors of passive CNPs with an emphasis on how the resonance wavelength can be tuned by controlling the material properties and radii of the various layers in the configuration. It is demonstrated that these passive CNPs have scattering cross sections much larger than their geometrical size, but their resonance strengths are attenuated because of the inherent losses in the metals. To overcome this limitation, we show how the introduction of active material into the CNPs can not only overcome these losses, but can actually lead to an amplification of the scattering of the incident field. We report several optimized active CNP designs, including ones based on quantum dot gain media and study their performance characteristics with particular attention to the effect of the location of the gain material on the performance of these designs. We investigate the ability to control the scattered field directivity of the CNPs in both their far- and near-field regions and propose designs with minimal backscattering and those emulating macroscopic nanojets. We compare data generated by initial efforts to experimentally prepare CNPs and compare against analytical and numerical simulation results. Finally, we suggest a variety of interesting future research directions. resonance wavelength can be tuned by controlling the material properties and radii of the various layers in the configuration. It is demonstrated that these passive CNPs have scattering cross sections much larger than their geometrical size, but their resonance strengths are attenuated because of the inherent losses in the metals. To overcome this limitation, we show how the introduction of active material into the CNPs can not only overcome these losses, but can actually lead to an amplification of the scattering of the incident field. We report several optimized active CNP designs, including ones based on quantum dot gain media and study their performance characteristics with particular attention to the effect of the location of the gain material on the performance of these designs. We investigate the ability to control the scattered field directivity of the CNPs in both their far- and near-field regions and propose designs with minimal backscattering and those emulating macroscopic nanojets. We compare data generated by initial efforts to experimentally prepare CNPs and compare against analytical and numerical simulation results. Finally, we suggest a variety of interesting future research directions