Dissertations / Theses on the topic 'Plasmons (Physics)'
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Kociak, Mathieu. "Supraconductivite et plasmons dans les nanotubes." Phd thesis, Paris 11, 2001. http://www.theses.fr/2001PA112101.
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Dans cet ouvrage, nous presentons deux types d'experiences sur des nanotubes uniques caracterises parallelement par microscopie electronique en transmission. Le premier type d'experiences a ete mene sur des jonctions metal-nanotube de carbone-metal. La resistance differentielle de ces jonctions a ete mesuree a des temperatures allant de 50 mk a 1k. Lorsque les contacts sont supraconducteurs, nous avons montre qu'il etait possible d'induire par effet de proximite un supercourant au sein d'une corde ou d'un tube monoparoi. Lorsque les contacts sont normaux, nous avons pu mettre en evidence une transition supraconductrice intrinseque dans des cordes de nanotubes a une temperature critique de environ 500 mk. Nous avons discute ces resultats en prenant en compte les parametres modifiant la supraconductivite dans des systemes a faible nombre de canaux. Nous avons montre ainsi la possibilite d'observer un transport ohmique et coherent dans des nanotubes de carbone. Dans le second type d'experiences, nous avons cherche a caracteriser la reponse dielectrique de nanotubes multifeuillets de carbone, nitrure de bore (bn) et de disulfure de tungstene (ws 2). Pour cela, nous avons effectue des mesures de spectroscopie de perte d'energie resolues spatialement. Nous avons d'abord montre l'adequation d'une description classique pour rendre compte des proprietes dielectriques (1-50 ev) de nanotubes a l'aide de mesures sur des nanotubes de carbone et bn. L'importance de l'anisotropie locale dans l'interpretation des spectres a ete demontree. Les memes experiences menees cette fois sur des tubes de ws 2 de parois d'epaisseur differentes a permis de mettre en evidence l'existence de modes electromagnetiques de surface de symetrie bien determinee resultant du couplage des modes des surfaces internes et externes. Une meme interpretation a permis de d'analyser la reponse dielectrique de tubes de carbone en termes classiques, meme lorsque la paroi se reduit a un plan monoatomique.
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Moazzezi, Mojtaba. "Quantum Coherence Effects Coupled via Plasmons." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1404550/.
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This thesis is an attempt at studying quantum coherence effects coupled via plasmons. After introducing the quantum coherence in atomic systems in Chapter 1, we utilize it in Chapter 2 to demonstrate a new technique of detection of motion of single atoms or irons inside an optical cavity. By taking into account the interaction of coherences with surface plasmonic waves excited in metal nanoparticles, we provide a theoretical model along with experimental data in Chapter 3 to describe the modification of Raman spectra near metal nanoparticles. We show in chapter 4 that starting from two emitters, coupled via a plasmonic field, the symmetry breaking occurs, making detectable the simultaneous existence of the fast super-radiance and the slow sub-radiance emission of dye fluorescence near a plasmonic surface. In Chapter 5, we study the photon statistics of a group of emitters coupled via plasmons and by the use of quantum regression theorem, we provide a theoretical model to fully investigate the dependence of photon bunching and anti-bunching effects to the interaction between atoms, fields and surrounding mediums.
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Jain, Prashant K. "Plasmons in assembled metal nanostructures." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/28207.
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Thesis (M. S.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2008.Committee Chair: El-Sayed, Mostafa A.; Committee Member: Lyon, L. Andrew; Committee Member: Sherrill, C. David; Committee Member: Wang, Zhong Lin; Committee Member: Whetten, Robert L.
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Ager, C. D. "Plasmons in microstructured semiconductor 2DEGs." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385904.
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Sadeghi, Hamed. "The dielectric function and plasmons in graphene." Thesis, California State University, Long Beach, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1527413.
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Deng, Haiming. "Nanoscale eengineering of infrared plasmons in graphene." Thesis, State University of New York at Stony Brook, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10140633.
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Surface plasmons are collective oscillations of free charge carriers confined in interface between two dielectrics, where the real part of the dielectric changes sign (e.g a metal-insulator interface such as gold film and air). The study of surface plasmon has been a popular research theme with potential applications utilizing the fact that the wavelength of plasmons can be many order smaller than that of the incident lights. The potential applications include transfer of information in hundreds of terahertz instead of upper limit of gigahertz in traditional wires, photodetectors with frequency range from terahertz to mid-IR, and nano-imaging. In our experiment, we use an IR near-field microscopy with resolution as low as 10nm but energy scale of micron range. This is achieved by shinning an AFM tip with infrared laser on top of the sample and collecting the scattered light from the sample. The spatial resolution proportional to where a is the size of the tip and the resolution can reach 10nm. This technique beats the diffraction limit of near-IR (10um) by over 1000x. The wavelength and amplitude damping of plasmon greatly depends on the property of free carriers in the material. While metals such as gold had been widely studied and shown promising results, a better platform with longer propagation length and shorter wavelength is needed for application. Graphenes supreme electronic transport property makes it apiii pears to be an excellent candidate for plasmonic. Graphene plasmon across a p-n junction will be discussed. Oxygen doping of graphene with different dosage via UV ozone is studied. Oxygen doping has shown promising results for graphene plasmon guide. Plasmon fringes are developed in the interior breaking the limit of boundary condition. The UV ozone treatment can be fine controlled and without damaging the graphene sheet. One can, in theory, mask and selectively dope to create a robust graphene plasmon circuit that is stable in room temperature.
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Nash, David James. "Grating and prism coupling to surface plasmons." Thesis, University of Exeter, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337803.
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Scheffler, Christopher M. "Localized Photoemission in Triangular Gold Antennas." Thesis, Portland State University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13808008.
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With the development of ultra-fast laser technology, several new imaging techniques have pushed optical resolution past the diffraction limit for traditional light-based optics. Advancements in lithography have enabled the straightforward creation of micron- and nanometer-sized optical devices. Exposing metal-dielectric structures to light can result in surface plasmon excitation and propagation along the transition interface, creating a surface plasmon polariton (SPP) response. Varying the materials or geometry of the structures, the plasmonic response can be tailored for a wide range of applications.
Photoemission electron microscopy (PEEM) has been used to image excitations in micron-sized plasmonic devices. With PEEM, optical responses can be characterized in detail, aiding in the development of new types of plasmonic structures and their applications. We show here that in thin, triangular gold platelets SPPs can be excited and concentrated within specific regions of the material (thickness ~50 nm); resulting in localized photoemission in areas of high electric field intensity. In this regard, the platelets behave as receiver antennas by converting the incident light into localized excitations in specific regions of the gold platelets. The excited areas can be significantly smaller than the wavelength of the incident light (λ ≤ 1 µm). By varying the wavelength of the light, the brightness of the excited spots can be changed and by varying the polarization of the light, the brightness and position can be changed, effectively switching the photoemission on or off for a specific region within the triangular gold structure.
In this work, the spatial distribution of surface plasmons and the imaging results from photoemission electron microscopy are reproduced in simulation using finite element analysis (FEA). In addition, we show that electromagnetic theory and simulation enable a detailed and quantitative analysis of the excited SPP modes, an explanation of the overall optical responses seen in PEEM images, and prediction of new results.
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Charbonneau, Robert. "Demonstration of a passive integrated optics technology based on plasmons." Thesis, University of Ottawa (Canada), 2001. http://hdl.handle.net/10393/9148.
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The theory surrounding plasmon-polariton wave propagation on infinitely wide thin metal film structures was rederived, understood and is presented. Mode dispersion curves as a function of metal thickness were obtained for various metals and wavelengths. Field distributions for various structures of interest were computed and are presented. Fresnel coefficients have been derived for an n -layer structure to simulate the expected reflectance measurements of attenuated total reflectance (ATR) experiments. ATR experiments have been performed to excite surface plasmon-polaritons on a 20 nm thick titanium (Ti)-gold (Au)-Ti film embedded in SiO2. Measurements of the sensitivity of the thin metal film infinite in width to incident polarisation were performed experimentally confirming the transverse magnetic (TM) nature of surface plasmon-polaritons. A first mask was designed to experimentally verify the optical mode confinement of a thin metal film finite in width. A second mask was designed with the knowledge acquired from the first one. (Abstract shortened by UMI.)
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Leal, Machado Francisco. "Using 2D vortex plasmons/phonon polaritons to control electronic selection rules." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/105594.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 69-73).
The discovery of orbital angular momentum (OAM) sustaining modes established a new degree of freedom by which to control not only the flow of light but also its interaction with matter. However, OAM sustaining modes have yet to be used to control the quantum dynamics of an electron in an atom or molecule due to the large length scale discrepancy between the wavelength of light and the size of the electron's orbital. In this work, we analyze the interaction between OAM carrying polariton vortex modes (for plasmon and phonon polaritons) and a hydrogen atom, and show that these modes can be used to engineer new selection rules in electronic transitions. Moreover, we show that these selection rules are robust to the displacement of the electronic system away from the vortex center. Perhaps more surprisingly, we find how displacement can be used favourably to tune which absorption process is dominant. Our findings are best suited to vortex modes that can be created in graphene, monolayer conductors, hBN, thin polar dielectrics, and many other polariton-sustaining thin materials. Another platform for observing these effects could be quantum dots interfaced with surface plasmons in-conventional metals.
by Francisco Leal Machado.
S.B.
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Held, Sylvain. "Photonique et plasmonique appliquées à la détection biomoléculaire." Phd thesis, Université Paris Sud - Paris XI, 2010. http://tel.archives-ouvertes.fr/tel-00742066.
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Les résonances de plasmon de surface sont des phénomènes liés à l'oscillation collective des électrons de conduction à la surface d'un métal sous l'influence d'une onde électromagnétique. Leur étude et leurs applications connaissent actuellement un grand essor. L'extrême sensibilité des conditions de résonance des plasmons aux variations du milieu environnant a conduit à la création de dispositifs de biocapteurs ultrasensibles et résolus en temps réel permettant de grandes avancées dans le domaine biomédical. Mais leur sensibilité et leur fonction peuvent être accrues par l'utilisation de structures nanométriques où le champ électromagnétique local est fortement amplifié. Dans ce contexte, cette thèse constitue un travail préliminaire à la réalisation de biopuce à résonance de plasmon de surface localisé. Elle porte d'une part sur l'étude et la mise au point de procédés innovant de fabrication de structures d'or périodiques sur différents substrats et dont les dimensions sont de l'ordre de la centaine de nanomètres. D'autre part, elle expose le développement et l'optimisation d'un banc expérimental de mesure en optique linéaire, permettant de réaliser des mesures angulo spectrales absolues à angle d'incidence et polarisation variables. Ces développements sont illustrés par les mesures réalisées sur nos structures. Ces travaux se placent en amont de la réalisation de systèmes de détection biologiques. Menés dans le cadre d'un partenariat pluridisciplinaire, ils posent des bases solides et nécessaires à la conception et l'étude de ce type de senseur et plus généralement à l'étude en champ lointain des phénomènes de résonances plasmoniques sur des structures nanométriques.
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Chen, Shumei. "Photon manipulation in plasmonic crystal." HKBU Institutional Repository, 2014. https://repository.hkbu.edu.hk/etd_oa/45.
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Plasmonic devices, consisting of subwavelength nanostructures at optical frequency, have been widely applied to many research .elds such as bio-sensing, super-resolution imaging, energy harvesting, nanolaser and so on. The strong con.ned electromagnetic .elds in the a.nity of nanostructures provides an e.cient channel to guide, enhance, and modulate light energy beyond the di.raction limit. In this thesis, we .rst studied the plasmonic devices in linear optical regime, especially from the view of phase information in the light matter interaction; then more e.orts were paid to the nonlinear plasmonics, in which the organic-plasmonic hybrid nanostructures provided a useful platform for demonstrating some interesting physical phenomena. Firstly, we studied the fundamental optical properties of typically propagating surface plasmonic polariton (SPPs), which were generated by plasmonic gratings. Optical elliptical response of excited SPPs was studied experimentally and theoretically in both amplitude and phase domains. Then we studied the strong coupling e.ect from plasmonic Fabry-Perot nanocavity, in which giant Rabi splitting phenomenon with a splitting energy ~ 148 meV was obtained experimentally. From these studies, the interaction of SPP wave with other resonant structures were well understood from the view point of phase evolution. Secondly, we moved from linear optics the nonlinear plasmonic optics and tried to understand how the plasmon enhancement acts on the nonlinear optical processes. In the .rst example, plasmon enhanced third harmonic generation (THG) on one dimensional gratings was experimentally demonstrated by integrating the nonlinear active medium into the plasmonic devices. Later, the generation of THG vortex beam was also realized by introducing hologram based plasmonic design. Lastly, we re-examined a conventional symmetry problem in nonlinear molecular optics. It was found the that the metacrystal, consisting of plasmonic molecule with feature size much larger than conventional molecules, also follows the conventional selection rules of third harmonic generation. We believe the knowledge we accumulated in this work also provides a strong background for our future studies on ultra-fast plasmonic switching, in which the all-optical low loss, optical switch can be realized by using the engineered optical properties of plasmonic devices.
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Chinowsky, Timothy Mark. "Optical multisensors based on surface plasmon resonance /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/5857.
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Nenninger, Garet Glenn. "High-resolution surface plasmon resonance biosensing /." Thesis, Connect to this title online; UW restricted, 2001. http://hdl.handle.net/1773/5840.
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Chekulaev, Dimitri. "Experimental study of ultrafast carrier dynamics and plasmons in nanostructures." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3306/.
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This thesis is devoted to the experimental investigation of ultrafast dynamics in silicon nanostructures and surface plasmonics by means of femtosecond lasers. First part of the research, ultrafast carriers dynamics in silicon nano-structures, is based on the time-resolved pump-probe reectivity method. A change in the density of excited carriers, as a response to the change of the excitation intensity, was extracted from the time-resolved re ectivity of crystalline nanopillars and nano-inclusions. The measurements were performed mainly in the sub-melting uence regime, at nearly normal incidence to the sample surface plane of the pump and probe beams. Both types of nano-structures have shown strong intensity dependent response comparing to bulk crystalline silicon. This enhanced response is attributed to a suppression of the diffusion processes in nanopillars and nonlinear response due to a constructive multilayer interference between the host matrix material, where silicon inclusions have been embedded, and the sublayers. Electron-phonon and recombination characteristic decay-times are extracted. The second part is devoted to sub-nanosecond decay of photoluminescence from siliconnitride amorphous structures. Particular structures have shown two radiative decay peaks. The second radiative peak is addressed to deep subband tail states, originated by the open bonds of the amorphous structure leading to the long radiative transition. The last part describes femtosecond-resolved plasmon-assisted dissociation of diatomic oxygen molecules in ultrahigh vacuum conditions. Asymmetric gold gratings have been utilised to create enhanced local electric elds originated from the optically excited surface plasmon resonances. Charged products of the dissociation process have been analysed by time-of-light linear drift mass spectrograph, while two-dimensional distribution has been achieved deploying Velocity Map Imaging technique. The dissociation process is found intensity dependent with strong non-linear prole. No correlation has been observed with background plasmon-enhanced electron emission.
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Biesso, Arianna. "Plasmonic field effects on the spectroscopic and photobiological function of the photosynthetic system of bacteriorhodopsin." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28162.
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Thesis (M. S.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2009.Committee Chair: Mostafa A. El-Sayed; Committee Member: Adegboyega K. Oyelere; Committee Member: Bridgette Barry; Committee Member: Joseph W. Perry; Committee Member: Mark R. Prausnitz.
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Pollard, Jeremy David. "Optical excitation of surface plasmons at metal/organic fluid boundaries." Thesis, University of Exeter, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253622.
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Chamberlain, Martyn Paul. "Electrons, phonons, coupled phonon-plasmons and their interactions in semiconductor heterostructures." Thesis, University of Essex, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254491.
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Yiu, Wai-kin, and 姚偉健. "Plasmonic enhancement of organic optoelectronic devices." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/211120.
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Plasmonics can be applied in a wide range of optoelectronic devices and it is induced by the interaction between incident light and conduction electrons. Resonance is induced by matching the photon energy and the frequency of electrons, which can cause the surface charge distribution and strengthens the electromagnetic field. Generally, plasmonics can be classified into surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR). SPR is the propagating wave, which occurs at interface between the dielectric and metal. LSPR is the non-propagating wave, which is the interaction between the metal nanoparticles (NPs) and incident light when the NP size is smaller than the light wavelength. In this thesis, plasmonic enhancement is studied to improve the performance of organic solar cells (OSCs) and light emission of organic semiconductors.
OSCs are low cost, light weight, flexibility, and solution process ability at room temperature. Short exciton diffusion length limits the thickness of active layer, which causes low photon absorption and consequently low current generation. In this part, gold nanoparticles (Au NPs) are blended into OSCs to enhance photovoltaic performance. Au NPs can induce the localized surface plasmon resonance (LSPR) which enhances the light absorption due to electromagnetic field generation. Also, light can be trapped by scattering to increase the optical path and thus enhance the charge carrier generation.
Film structure and 1D nanostructure of organic semiconductor are studied by their photoluminescence (PL) intensity. Generally, the PL intensity can be enhanced by SPR. Excitation energy can induce the surface plasmon (SP) instead of photon, which can amplify the spontaneous emission and stimulated emission. Compared to thin films, 1D organic structures achieve higher PL enhancement because they can trap the light more efficiently by Fabry-Pérot cavity. Different morphologies of organic semiconductor are synthesized and it is found that hexagonal plates can obtain better PL enhancement because of the Fabry-Pérot cavity mode.published_or_final_version
Physics
Master
Master of Philosophy
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Li, Hongjie. "Mathematical study on plasmon materials and their applications." HKBU Institutional Repository, 2019. https://repository.hkbu.edu.hk/etd_oa/642.
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This thesis is concerned with the mathematical analysis of plasmon materials and their applications, including the cloaking effect and the super-resolution in imaging induced by plasmon resonances. We consider these phenomena in two regimes, namely, the quasi-static regime and the finite-frequency regime beyond the quasi-static approximation. In the quasi-static regime, we first show that the plasmon resonance could occur for the elastic system in both two and three dimensions. By establishing the primal and dual variational principles and constructing the perfect plasmon waves, we prove that the plasmon resonance can occur for a delicate plasmonic configuration with appropriately choosing Lame parameters. We also apply the spectral method to show the phenomenon of cloaking due to anomalous localized resonance (CALR) through analyzing the spectral system of the Neumann-Poincare (N-P) operator. Moreover, based on the obtained spectral properties of the N-P operator, we strictly verify the plasmon resonance in the quasi-static approximation and construct a general and novel class of plasmonic configurations to ensure the occurrence of the CALR, which significantly generalizes the existing research on plasmon resonances in the literature. Finally, we derive the perturbed displacement field associated with a given elastic source field with the presence of nanoparticles. By analyzing the spectral properties of the associated Neumann-Poincare operator, the leading-order term of the perturbed elastic wave field is determined, which could help to achieve the super-resolution in the elastic imaging. For the case beyond the quasi-static approximation, we develop two approaches to achieve the plasmon resonance. The first one is achieved by the explicit construction, though it is very delicate and subtle. We first show that the cloaking due to anomalous localized resonance could occur for the Helmholtz system within finite frequencies beyond the quasi-static approximation. More precisely, by investigating the spectral system of the corresponding Neumann-Poincare operator within finite frequencies, we include the plasmon parameters, the shape of the plasmonic inclusion and the source term as a whole system to achieve the phenomenon of the cloaking due to anomalous localized resonance. Furthermore, we show that the surface plasmon resonance and the cloaking effect can occur for the Maxwell system beyond the quasi-static approximation by calculating the spectral system of the matrix-valued integral operator. The other one is achieved via the localization and geometrization. Through the investigation on the eigenfunctions of the corresponding Neumann-Poincare operator, we show that the plasmon resonance occurs locally near the high-curvature point of the plasmonic inclusion. It is worth mentioning that we present the first investigation in the literature on the geometric structures of the Neumann-Poincare eigenfunctions.
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Wang, Zilan. "Characteristics of plasmonic waveguide coupling and propagation." HKBU Institutional Repository, 2012. https://repository.hkbu.edu.hk/etd_ra/1393.
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Deng, Junhong. "Numerical and analytical studies of ciricular dichroism of plasmonic nanospirals generated by glancing angle deposition /Deng Junhong." HKBU Institutional Repository, 2017. http://repository.hkbu.edu.hk/etd_oa/345.
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As emerging chiral metamaterials, plasmonic nanospirals (NSs) show strong optical activity that is expected to enhance the enantiodiscrimination of chiral molecules or help in the design of a new generation of integrated optical devices. The study of the optical activity of plasmonic NSs is still in its infancy, and no analytical model exists to describe their chiroptical mechanism. In this study, numerical and analytical simulations are devised to investigate the optical activity of plasmonic NSs that are generated by glancing-angle deposition. The findings will pave the way for the development of novel optical and optoelectronic devices with integrated functions. The CD spectrum of a closely packed random AgNS array has two CD peaks in the UV and visible regions with opposite signs. The pitch-normalized CD in the UV regime tends to be independent of the helical pitch, but that in the visible regime decreases in amplitude as helical pitch increases. The difference can be explained using an analytical LC circuit model and finite-element method simulation. The LC circuit model is used to quantitatively evaluate the chiroptical contribution. It is revealed that radiative loss makes an important chiroptical contribution to the two CD modes and that the visible CD mode receives a greater contribution from radiative loss than does the UV CD mode. Finally, the heterochiral biaxial AgNS arrays alter the sign of the visible CD by switching the incident direction, which shows that the arrays can function as circular polarizers in the visible regime. Furthermore, when AgNSs are deposited on a polymer substrate coated with indium tin oxide, the chiroptical flexible thin film has excellent chiroptical stability when exposed to forward mechanical bending, paving the way for the development of flexible or wearable chiroplasmonic devices.
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Hosseini, Alast Fatemeh. "Active plasmonic nanostructures /Fatemeh Hosseini Alast." HKBU Institutional Repository, 2017. http://repository.hkbu.edu.hk/etd_oa/369.
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In principle, the surface plasmon polaritons, at the planar metal/dielectric interface, cannot be excited by incident light. However momentum transfer from incident light to Surface Plasmon Polaritons (SPPs) inside the light line can be achieved by adding a periodic structure at the interface. The lattice wave vector can compensate the difference between incident light and surface wave momentum and satisfy momentum matching requirement. Two methods are commonly used to achieve this goal: first, using prism and second, surface engineering using different array apertures at the metal/dielectric interfaces. In this thesis, the ruled grating pattern at the metal/dielectric interface using conventional photolithography technique was fabricated. The dimension of ruled grating pattern is proportional to expanding/collimating system in the interference set-up. In fact, a large area grating can be utilized for many optoelectronic applications with greater efficiency. In this work, large area grating pattern, 10×10 mm2, on top of the microcavity structure was integrated that permitting cavity mode-SPP coupling. Hence, Rabi-like splitting was observed from the hybrid plasmonic microcavity. The splitting was created from the coupling of cavity mode with the surface plasmon polariton mode; anti-crossing was observed alongside the modal conversional channel on the reflection light measurement. In following, it was experimentally explored the effect of using organic fluorescent molecules inside the hybrid plasmonic microcavity. Accordingly we integrated large area ruled metal grating onto photonic microcavity and assessed the cavity mode-SPP coupling with reflectivity measurement. We got much more grounded modal coupling in presence of florescent molecules within photonic cavity. The anti-crossing was detected with enormous Rabi-like splitting energy at 280 meV in the strong coupling regime. Besides we compared the coupling strength of plasmonic microcavities with various cavity lengths to explore the absorption impact.
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Johnston, Kyle S. "Planar substrate surface plasmon resonance probe with multivariant calibration /." Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/6069.
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Rohde, Charles Alan. "Coherent plasmon coupling in spherical metallodielectric multilayer nanoresonators /." Connect to title online (Scholars' Bank) Connect to title online (ProQuest), 2008. http://hdl.handle.net/1794/8592.
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Thesis (Ph. D.)--University of Oregon, 2008.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 156-162). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.
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Wang, Chuandao Charlie, and 王传道. "Organic solar cells towards high efficiency: plasmonic effects and interface engineering." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48329654.
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Organic solar cells (OSCs) are promising candidates for solar light harvesting due to their standout advantages both in material properties and manufacturing process. During past decades, remarkable progress has been achieved. Efficiency for single-junction cells over 9% and tandem cells over 10% has been reported. For high performance OSCs towards commercialization, sufficient light absorption and high quality buffer layers are still two challenges, which are addressed in this thesis by investigating the plasmonic effects on OSCs and interface engineering.
Here, the mechanisms of plasmonic effects on OSC are explored by incorporating metallic Au nanoparticles (NPs) in individual anode buffer layer and active layer, respectively, and finally in both layers simultaneously. When Au NPs are incorporated into the buffer layer, surface plasmonic resonance (SPR) induced absorption enhancement due to incorporation of Au NPs is evidenced theoretically and experimentally to be only minor contributor to the performance improvement. The increased interfacial contact area between the buffer layer and active layer, together with the reduced resistance of the buffer layer due to the embedded Au NPs, are revealed to benefit hole collection and thus are main contributors to the performance improvement. When Au NPs are embedded in the active layer, Au NPs induced SPR indeed contributes to enhanced light absorption. However, when large amount of Au NPs are incorporated, the negative effects of NPs on the electrical properties of OSCs can counter-diminish the optical enhancement from SPR, which limits the overall performance improvement. When Au NPs are embedded into both layers, both advantages of incorporating NPs in individual layers can be utilized together to achieve more pronounced improvement in photovoltaic performance; as a result, accumulated enhancements in device performance can be achieved. The results herein are applicable to other metallic NPs such as Ag NPs, Pt NPs, etc. The study herein has clarified the degree of contribution of SPR effects on OSCs and revealed the mechanisms behind. It has also highlighted the importance of considering both optical and electrical effects when employing metallic NPs as strategies to enhance the photovoltaic performance of OSCs. Consequently, the study contributes both physical understanding and technological development of applying metallic NPs on OSCs.
Regarding interface engineering, we first propose a simple method to modify the substrate work function for efficient hole collection by using an ultra-thin ultraviolet-ozone treated Au. The method can be used in other situations such as modifying the work function of multilayer graphene as transparent electrode. Then we propose a general method to synthesize solution-processed transition metal oxides (TMOs). Besides high material quality, desirable electrical properties, and good stability, our method stands out particular in that the synthesized TMOs can be dispersed in water-free solvents and the TMO films require only low temperature treatment, which is very compatible with the organic electronics. Our method can also be used to synthesize other TMOs other than the demonstrated molybdenum oxide and vanadium oxide. The proposed method herein is applicable in semiconductor industry.published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy
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Intravaia, Francesco. "Effet Casimir et interaction entre plasmons de surface." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2005. http://tel.archives-ouvertes.fr/tel-00009755.
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Dans cette thèse on discute l'influence des plasmons de surfaces sur l'effet Casimir entre deux miroirs métalliques plans et parallèles placés à une distance arbitraire. En utilisant le model plasma pour décrire la réponse optique du métal, on exprime l'énergie de Casimir comme une somme des contributions associées aux modes évanescents relatifs aux plasmons de surface et aux modes propagatifs de la cavité. Contrairement à une ce qu'on pouvait attendre, la contribution des modes plasmoniques est essentielle à toute distance afin d'assurer le correct résultat pour l'énergie de Casimir. Un des deux modes plasmoniques génère une contribution répulsive qui compense la contribution attractive provenant des modes propagatifs de la cavité, alors que les deux contributions, prises séparément, sont beaucoup plus importantes que la valeur réelle pour l'énergie de Casimir. Cela suggère qu'il est possible d'ajuster le signe de la force de Casimir en manipulant les plasmons de surface.
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Bonnand, Clément. "Couplage fort entre plasmons de surface et excitons de semiconducteur organique." Phd thesis, Université Claude Bernard - Lyon I, 2006. http://tel.archives-ouvertes.fr/tel-00122048.
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Ce travail de thèse porte sur l'étude des propriétés optiques de matériaux proche de surface métallique. Nous avons mis en évidence un régime de couplage fort entre les plasmons de surface, se propageant à l'interface métal diélectrique, et les excitons desemiconducteur organiques. Ceux-ci sont formé de colorants J-agrégés. Le couplage fort se traduit par l'apparition d'états mixtes plasmons-excitons : les polaritons. Des mesures de réflectométrie, réalisées sur des échantillons présentant une couche de J-agrégats déposée sur un film d'argent, nous permettre de mettre en évidence un anticroisement dans le relations de dispersion du plasmon et de l'exciton, ce qui est caractéristique du couplage fort. L'émission des nouveaux états polaritoniques a été étudier dans deux géométries différentes : en utilisant des échantillons présentant une couche d'argent plane et avec des
films d'argent nanostructuré dans une géométrie de cross-coupling.
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Bhatta, Hari Lal. "UV Magnetic Plasmons in Cobalt Nanoparticles." Thesis, University of North Texas, 2019. https://digital.library.unt.edu/ark:/67531/metadc1505221/.
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The main goals of this research were to fabricate magnetic cobalt nanoparticles and study their structural, crystal structure, optical, and magnetic properties. Cobalt nanoparticles with average particle size 8.7 nm were fabricated by the method of high temperature reduction of cobalt salt utilizing trioctylphosphine as a surfactant, oleic acid as a stabilizer, and lithium triethylborohydride as a reducing reagent. Energy-dispersive X-ray spectroscopy (EDX) analysis confirmed the formation of cobalt nanoparticles. High resolution transmission electron microscopy images show that Co NPs form both HCP and FCC crystal structure. The blocking temperature of 7.6 nm Co NPs is 189 K. Above the blocking temperature, Co NPs are single domain and hence showed superparamagnetic behavior. Below the blocking temperature, Co NPs are ferromagnetic. Cobalt nanoparticles with a single-domain crystal structure support a sharp plasmon resonance at 280 nm. Iron nanoparticles with average particle size 4.8 nm were fabricated using chemical reduction method show plasmon resonance at 266 nm. Iron nanoparticles are ferromagnetic at 6 K and superparamagnetic at 300 K.
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Rahbany, Nancy. "Towards integrated optics at the nanoscale : plasmon-emitter coupling using plasmonic structures." Thesis, Troyes, 2016. http://www.theses.fr/2016TROY0003/document.
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L'objectif de ce travail de thèse est d'étudier le couplage plasmon-émetteur dans des structures plasmoniques hybrides, visant à renforcer l’interaction lumière-matière à l'échelle nanométrique. Contrairement aux cavités optiques dont le volume de modes est limité par la diffraction, les cavités plasmoniques offrent un unique avantage d’efficacité du confinement sub-longueur d'onde. Cela peut conduire à l’accroissement de la fluorescence des émetteurs placés dans leur voisinage. Pour cela, nous proposons comme dispositif de focalisation une structure intégrée d’un réseau annulaire avec des nanoantennes afin de garantir une meilleure efficacité. Ce dispositif bénéficie du couplage entre des plasmons polaritons de surface (SPP) qui se propagent à partir du réseau et des plasmons localisés de surface (LSP) localisés aux niveaux des nanoantennes afin de parvenir à une augmentation de champ plus élevée. Nous présentons une étude de caractérisation de la plate-forme plasmonique constitué du réseau de diffraction métallique annulaire, d’une nanoantenne en étoile, et la structure intégrée réseau/nanoantenne. Nous montrons comment cette structure peut conduire à une plus grande émission des molécules de colorants ainsi que de centre SiV du diamant. La combinaison du confinement sub-longueur d'onde des LSP et l'énergie élevé des SPP dans notre structure conduit à une focalisation précise qui peut être mis en œuvre pour étudier le couplage plasmon-émetteur dans les régimes de couplage faibles et fortsThere is a growing interest nowadays in the study of strong light-matter interaction at the nanoscale, specifically between plasmons and emitters. Researchers in the fields of plasmonics, nanooptics and nanophotonics are constantly exploring new ways to control and enhance surface plasmon launching, propagation, and localization. Moreover, emitters placed in the vicinity of metallic nanoantennas exhibit a fluorescence rate enhancement due to the increase in the electromagnetic field confinement. However, numerous applications such as optical electronics, nanofabrication and sensing devices require a very high optical resolution which is limited by the diffraction limit. Targeting this problem, we introduce a novel plasmonic structure consisting of nanoantennas integrated in the center of ring diffraction gratings. Propagating surface plasmon polaritons (SPPs) are generated by the ring grating and couple with localized surface plasmons (LSPs) at the nanoantennas exciting emitters placed in the gap. We provide a thorough characterization of the optical properties of the simple ring grating structure, the double bowtie nanoantenna, and the integrated ring grating/nanoantenna structure, and study the coupling with an ensemble of molecules as well as single SiV centers in diamond. The combination of the sub-wavelength confinement of LSPs and the high energy of SPPs in our structure leads to precise nanofocusing at the nanoscale, which can be implemented to study plasmon-emitter coupling in the weak and strong coupling regimes
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Maximino, Fabio Lombardi. "Interferência da rugosidade superficial na propagação de plasmons de superfície em filmes de Au." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-16012017-110032/.
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Com os desenvolvimentos tecnológicos na área da nanociência e nanotecnologia pode se realizar novas pesquisas de fronteira. Entres estas pesquisas uma de muito interesse é sobre as interações nas escalas nanométricas e micrométricas. E com o desenvolvimento de novos equipamentos para esta área conseguimos observar e entender interações como entre a luz e materiais condutores como os metais. Esta interação produz ondas densas de elétrons, estas ondas são conhecidas como plásmons. Os estudos acerca dos plásmons estão sendo desenvolvidos desde os anos 80, e com as novas tecnologias podemos cada vez mais refinar e potencializar os resultados sobre estes assuntos. As pesquisas mais atuais sobre este tema veem gerando inúmeros desenvolvimentos nas áreas de gravação magneto-ótica, microscopia, detectores moleculares biológicos, entre outras. Os plasmons são oscilações que se confinam na superfície dos materiais, que têm como característica serem ondas evanescentes, por isso eles precisam ser observados em campo próximo. Com o intuito de observar e compreender a propagação destes plasmons de superfície (SPs) foi utilizado um microscópio ótico de varredura em campo próximo (SNOM). Este equipamento permite imagens óticas de campo próximo simultaneamente com imagens topográficas da superfície do material. Em trabalhos anteriores foi possível caracterizar a propagação dos SP em filmes de Ag e Au. Uma característica observada foi um padrão de oscilação ótica dentro da propagação dos SP. Visando entender esta oscilação, estudamos a influência da rugosidade dos filmes nesta oscilação dentro da propagação dos SP. Com o SNOM foi possível analisar a influência da rugosidade sobre a oscilação na propagação dos SP. Este tipo de oscilação já havia sido mostrado em artigos na literatura, porém nunca antes foi analisado em profundidade ou foi dada uma explicação clara para sua existência. Visando produzir filmes com rugosidades diferentes, foi utilizado um sistema de \"magnetron sputtering\" disponível no Laboratório de Materiais Magneticos da USP. Usando-se diferentes temperaturas de deposição e materiais codepositados se produziu filmes de rugosidades distintas. As rugosidades variaram de 1 nm à 40 nm, com isto se pode constatar que existe uma oscilação dentro da propagação dos SP que fica mais evidente, e sofre perturbações, conforme o filme é mais rugoso. Porém também foi observado que mesmo com filmes muito lisos esta oscilação permanece, podendo ser algo intrínseco da própria propagação do SP, e quanto maior rugosidade superficial mais intensa e irregular esta oscilação.New border technology researches can be made from the technological developments in nanocience and nanotechnology, among which, the research on nanometric and micrometric scales is of great interest. With the development of new equipment for this area, we are able to observe and understand interactions between light and conductive materials, such as metals, for example. This interaction produces dense electron waves, these waves are known as Plasmon. Studies on Plasmon have been developed since the 1980\'s and, with the new technologies we can constantly refine and potentialize the results on this matter. The more recent researches on the theme have been generating innumerous developments in the areas of magneto-optical recording, microscopy, biological molecular detectors, among others. Plasmon\'s consist in confined oscillations in the surfaces of materials, characterized for being evanescent waves, for that reason they have to be observed in near field. In order to observe and comprehend the propagation of these Surface Plasmon (SP) a scanning near-field optical microscope (SNOM) was used. This equipment allows near field images to be formed concomitantly with topographic images of the material\'s surface. In previous works it was possible to characterize the propagation of the SP in Ag and Au films. One observed characteristic was an oscillation pattern within the SP propagation. Aiming to understand this oscillation, we studied the influence of the films rugosity on the oscillation within the propagation of the SP. With SNOM it was possible to analyze the influence of the rugosity on the oscillation within the propagation of the SP. This type of oscillation had already been observed in the literature, but it had never before been analyzed in depth or a clear explanation for its existence has been given. Aiming to produce films with different rugosities, a magnetron sputtering system was used. Using different deposition temperatures and co-deposited materials we produced films with different rugosities. The rugosities vary from 1 nm to 40 nm, with this we could note that there is an oscillation within the SP propagation which are more evident and suffer disturbances, as the film\'s rugosity increases. Although it was observed that even in very smooth films this oscillation remains, which can indicate an intrinsic character of the SP propagation and also, the larger the rugosity, more intense and irregular this oscillation.
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Carrega, Matteo. "Coulomb drag and Dirac plasmons in novel 2D electron systems." Doctoral thesis, Scuola Normale Superiore, 2014. http://hdl.handle.net/11384/85870.
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[from the introduction]: This Thesis focusses on
the physics of e-e interactions in single-layer graphene and on the role of interlayer e-e
interactions in vertical heterostructures comprised of two closely spaced graphene sheets.
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Schumann, Robert Paul. "Surface plasmon random scattering and related phenomena." Thesis, Connect to title online (Scholars' Bank) Connect to title online (ProQuest), 2009. http://hdl.handle.net/1794/10297.
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Typescript. Includes vita and abstract. Includes "Monte Carlo SPP Scattering Simulation Program" (leaves 107-123) Includes bibliographical references (leaves 124-129) Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.
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Goffard, Julie. "Etude du couplage entre des nanocristaux de silicium et des plasmons de surface localisés." Thesis, Troyes, 2014. http://www.theses.fr/2014TROY0012/document.
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La découverte de la photoluminescence du silicium sous sa forme nanométrique a ouvert la voie de l’utilisation du silicium dans les composants optoélectroniques. Cependant cette photoluminescence reste trop peu efficace et de nombreuses recherches portent aujourd’hui sur l’amélioration des propriétés optiques du silicium. Ce travail de thèse s’intéresse particulièrement à l’utilisation de plasmons de surface localisés afin d’améliorer les propriétés optiques de nanocristaux de silicium. Grâce au contrôle de tous les paramètres géométriques des nanocristaux de silicium et des nanoparticules métalliques lors de la fabrication des échantillons, il a été possible d’étudier les phénomènes physiques du couplage entre ces deux objets. Une modification de l’émission des nanocristaux de silicium en fonction de la distance, de la taille et de la nature des nanoparticules métalliques a été étudiée. Grâce au développement de différentes techniques de caractérisation optique, il a été possible de montrer que la photoluminescence des nanocristaux de silicium était modifiée à la fois spectralement et spatialement par les plasmons de surface localisés. Ce travail montre que grâce aux plasmons de surface localisés il est possible de grandement améliorer la photoluminescence des nanocristaux de silicium et ainsi il est possible d’imaginer de nouveaux composants optoélectroniques à base de silicium et de plasmonsThe discovery of photoluminescence of nanometric silicon paves the way to use silicon in optoelectronic devices. However this photoluminescence remains low and a lot of works aim at improving silicon optical properties. In this dissertation we study localized surface plasmons to improve optical properties of silicon nanocrystals. Thanks to the control of all geometrical parameters of silicon nanocrystals and metallic nanoparticles during the fabrication process, the coupling process between these two objects has been studied. The modification of silicon nanocrystals emission as a function of the distance, the size and the nature of metallic nanoparticles has been investigated. Thanks to the development of experimental optical characterization techniques we showed that silicon nanocrystals photoluminescence is modified both spectrally and spatially by localized surface plasmons. This work shows that it’s possible to enhance silicon’s optical properties and thus to devise optoelectronic devices with silicon and plasmons
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Nicoletti, Olivia. "Mapping surface plasmons of metal nanoparticles with electron energy-loss spectroscopy." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608025.
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Lin, Jie (physicist). "Interaction of Plasmons and Excitons for Low-Dimension Semiconductors." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc799475/.
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The effects of surface plasmon for InGaN/GaN multi-quantum wells and ZnO nanoparticles optical linear and nonlinear emission efficiency had been experimentally studied. Due to the critical design for InGaN MQWs with inverted hexagonal pits based on GaN, both contribution of surface plasmon effect and image charge effect at resonant and off resonant frequencies were experimentally and theoretically investigated. With off- resonant condition, the InGaN MQWs emission significantly enhanced by metal nanoparticles. This enhancement was caused by the image charge effect, due to the accumulation of carriers to NPs region. When InGaN emission resonated with metal particles SP modes, surface Plasmon effect dominated the emission process. We also studied the surface plasmon effect for ZnO nanoparticles nonlinear optical processes, SHG and TPE. Defect level emission had more contribution at high incident intensity. Emissions are different for pumping deep into the bulk and near surface. A new assumption to increase the TPE efficiency was studied. We thought by using Au nanorods localized surface plasmon mode to couple the ZnO virtual state, the virtual state’s life time would be longer and experimentally lead the emission enhancement. We studied the TPE phenomena at high and near band gap energy. Both emission intensity and decay time results support our assumption. Theoretically, the carriers dynamic mechanism need further studies.
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Garnier, Jérôme. "Polymer electrochromism and surface plasmons combined on metallic diffraction gratings." Thesis, Linköping University, Department of Science and Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11522.
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All conducting polymers are potentially electrochromic, owing to the injection of charge carriers that changes their electronic structure and results in a shift of their optical absorption towards higher wavelengths. PEDOT-PSS and PEDOT-S are very promising materials in terms of electrochromic properties, due to the good contrast existing between their doped and undoped forms. However this contrast has to be enhanced in order to design more efficient electrochromic devices, and new solutions should thus be found in order to solve this issue.
Surface plasmons are described as electromagnetic waves propagating along the surface between a dielectric and a metal. Coupled to an incident radiation, they create an energy loss in the light transmitted and reflected by the interface. When the metallic surface is periodically corrugated, this absorption phenomenon due to plasmonic resonance occurs at a specific wavelength that depends on several parameters, such as the incidence angle, the dielectric constants of the two media and the grating period. By coating metallic gratings with electrochromic polymers, we may thus be able to trigger a plasmonic absorption at a given wavelength and shift it upon reduction or oxidation of the material.
Electrochromic devices consisting of PEDOT-PSS or PEDOT-S spin-deposited on gold and silver gratings were investigated by UV-visible reflectance measurements. The periodically corrugated structures were reproduced from commercial gratings by soft nanolithography and were analyzed by AFM. Some electrochromic cells exhibited new colors or a high shift of the plasmonic resonance upon redox switching of the polymer film. Depending on the step and the nature of the grating employed, this shift could reach 20 nm in the case of PEDOT-PSS and more than 100 nm for PEDOT-S. A theoretical model was found to predict the wavelength of plasmonic excitation and the orientation of the shift.
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Cilwa, Katherine E. "Surface Plasmons Polaritons and Single Dust Particles." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1304532704.
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Perez, Florent. "Plasmons dans un potentiel unidimensionnelEtude par spectroscopie Raman de fils quantiques gravés." Phd thesis, Université Pierre et Marie Curie - Paris VI, 1998. http://tel.archives-ouvertes.fr/tel-00285443.
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Nous avons étudiés des fils quantiques dopés de semi-conducteurs gravés par spectroscopie de diffusion Raman. Nous avons observés les excitations du gaz d'électrons. Celles-ci présentent des règles de sélection différentes de celles établies pour les systèmes bi-dimensionnels. Nous avons montré théoriquement qu'elles proviennent de la modification de la structure du champ électromagnétique local provoquée par la géométrie particulière des fils gravés. Pour cela nous avons dû calculer le champ local et l'introduire dans la section efficace de diffusion Raman pour en déduire les règles de sélection de toutes les excitations. Cela a permis de déterminer sans équivoque la nature des excitations qui sont des plasmons. Aucune excitations à une particule ni fluctuations de densité de spin n'a été observées. Nous avons étudié l'évolution continue des dispersions de ces plasmons lorsque la largeur du fil est réduite de 1 micromètre à 30 nm. Jusqu'à 60 nm, celles-ci sont en très bon accord avec les résultats d'un modèle hydrodynamique. Au dessous de 60 nm, la comparaison avec un modèle RPA s'impose. Le plasmon intra-bande dispersif est observé jusqu'à 45 nm, largeur en dessous de laquelle les spectres Raman sont dominés par des excitations localisées qui nécessitent une analyse ultérieure pour en déterminer clairement leur nature. Nous montrons à l'aide du modèle RPA que nous avons atteint la limite quantique pour un fil de largeur 55 nm. Une gamme étroite de fils dont les largeurs sont comprises entre 55 nm à 45 nm permet donc l'étude de gaz strictement unidimensionnel.Nous avons cherché à déterminer la contribution de la forte illumination dans les conclusions précédentes. Nous avons utilisé pour cela la spectroscopie de magnéto-transmission infra-rouge qui ne modifie pas les conditions d'équilibre du gaz d'électrons. Une largeur critique de 130 nm a été extraite, en dessous de laquelle nous n'avons plus aucun signe de la présence d'électrons libres. La comparaison des mesures Raman et infra-rouge a permis l'établissement et la validation d'un modèle microscopique du potentiel de confinement présent dans les fils. Enfin nous avons fabriqués des échantillons de géométries plus complexes. L'observation et l'analyse par diffusion Raman des plasmons dans ces fils a montré que nous pouvions contrôler la géométrie du potentiel confinant les électrons et a mis en évidence des effets nouveaux tels que le repliement et le confinement de plasmons unidimensionnels.
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Ning, Ding. "Analytical and Numerical Models of Multilayered Photonic Devices." University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1207712683.
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Li, Xuanhua, and 李炫华. "Plasmonic-enhanced organic solar cells." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/197526.
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Organic solar cells (OSCs) have recently attracted considerable research interest. However, there is a mismatch between their optical absorption length and charge transport scale. Attempts to optimize both the optical and electrical properties of the photoactive layer of OSCs have inevitably resulted in demands for rationally designed device architecture. Plasmonic nanostructures have recently been introduced into solar cells to achieve highly efficient light harvesting. The remaining challenge is to improve OSC performance using plasmonic nanotechnology, a challenge taken up by the research reported in this thesis. I systematically investigated two types of plasmonic effect: localized plasmonic resonances (LPRs) and surface plasmonic resonances (SPRs).
Broadband plasmonic absorption is obviously highly desirable when the LPR effect is adopted in OSCs. Unfortunately, typical nanomaterials possess only a single resonant absorption peak, which inevitably limits the power conversion efficiency (PCE) enhancement to a narrow spectral range. To address this issue, I combined Ag nanomaterials of different shapes, including nanoparticles and nanoprisms. The incorporation of these mixed nanomaterials into the active layer resulted in wide band absorption improvement. My results suggest a new approach to achieving greater overall enhancement through an improvement in broadband absorption.
I also explored the SPR effect induced by a metal patterned electrode with two parts. Most reports to date on back reflector realization involve complicated and costly techniques. In this research, however, I adopted a polydimethylsiloxane (PDMS)-nanoimprinted method to produce patterned back electrodes in OSCs directly, which is a very simple and efficient technique for realizing high-performance OSCs in industrial processes. Besides, a remaining challenge is that plasmonic effects are strongly sensitive to light polarization, which limits plasmonic applications in practice. To address this issue, I designed three-dimensional patterns as the back electrode of inverted OSCs, which simultaneously achieved highly efficient and polarization-independent plasmonic OSCs.
In addition to investigating the two types of plasmonic effect individually, I also investigated their integrated function by introducing both LPRs and SPRs in one device structure. With the aim of achieving high-performance OSCs, I first demonstrated experimentally a dual metal nanostructure composed of Au nanoparticles (i.e. LPRs) embedded in the active layer and an Ag nanograting electrode (i.e. SPRs) as the back reflectors in inverted OSCs, which can generate a very strong electric field, in a single junction to improve the light absorption of solar cells. As a result, the PCE of the OSC reached 9.1%, making it one of the best-performing OSCs reported to date. In addition, as an important extension, I subsequently achieved tremendous near-field enhancement owing to multiple couplings, including nanoparticle-nanoparticle (LPR-LPR) couplings and nanoparticle-film (LPR-SPR) couplings, by designing a novel nanoparticle-film coupling system through the introduction of ultrathin monolayer graphene as a well-defined sub-nanogap between the Ag nanoparticles and Ag film. The graphene sub-nanogap is the thinnest nanogap (in atomic scale terms) to date, and thus constitutes a promising light-trapping strategy for improving future OSC performance.published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy
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Poncheri, Adam James. "Plasmonic field effects of silver nanoparticle monolayers on poly(phenylene ethynylene) fluorescent polymers of different chain length." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41099.
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The literature on nanomaterials has been flooded with new shapes, sizes, and compositions of nanostructures. The process of developing and characterizing these particles has been broadly accomplished and many interesting and promising properties have been revealed for application in current and developing technologies. In particular, the phenomenon of surface plasmon resonance seen in metallic gold and silver nanoparticles has drawn substantial interest. It has been established that the electromagnetic fields surrounding plasmonic particle surfaces can influence the properties of nearby systems, causing them to experience effects such as enhanced absorption and emission of light or drastically increased conductivity. For this reason, plasmonic nanoparticles are being applied to an endless number of applications for new materials.
This thesis investigated the effects of silver nanocube (AgNC) arrays on the photophysical properties of poly(paraphenyleneethynylene) (PPE) fluorescent polymers, a particularly relevant material to the applications of organic-electronics. AgNCs were selected because of their particularly strong plasmonic field, which is enhanced at the sharp features of the cubes. The PPE polymer is an exceptionally fluorescent conjugated polymer that often serves as a building block for polymer-based sensing applications. By monitoring the absorption and emission of the PPE polymer, a better understanding of plasmonic effects on this polymer system was obtained. Compression of the monolayer of AgNCs on the surface of a Langmuir-Blodgett trough can be used for control of interparticle distance and, thus, the plasmon field intensity felt by an adsorbed layer of PPE polymer.
In the Chapter 4, PPE (n = 15) emission was monitored as a function of the AgNC plasmonic field. A two-photon process was found to explain the unusual increase then decrease of the fluorescence intensity. This observation was attributed to exciton-exciton annihilation processes within the polymer. The annihilation process is initiated by large enhancements of the polymer absorption rate when plasmonic fields are at their highest (when the AgNCs are compressed to short interparticle distances).
In chapter 5, the optical properties of PPE polymers as a function of their chain length and the AgNC density were examined. A simple study was conducted to consider the conformational/geometrical effects on PPE that were caused by the deposition of PPE onto the AgNC topography. In this study, the structure of the absorption and emission profiles were evaluated and used as evidence of polymer interchain interactions, planarization, and even the potential generation of oligomeric species through breaking of conjugation.
Fundamental interactions between materials must be evaluated and optimized prior to their use in devices. This thesis serves to shed a little bit of light on the interaction of a well-defined plasmonic particle with a conjugated polymer. The Langmuir-Blodgett technique serves as a critical tool in applying these colloidally produced nanoparticles to 2D arrays in practical applications. The observation of exciton-exciton annihilation at low-energy excitation is an entirely new phenomenon that was initiated by the plasmonic properties of metal nanoparticles. It is the hope of the author that the results contained herein can aide in the use of plasmonic nanoparticles in future devices.
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Mozsolits, Henriette 1971. "Surface plasmon resonance spectroscopy for the study of peptide-membrane interactions." Monash University, Dept. of Biochemistry and Molecular Biology, 2001. http://arrow.monash.edu.au/hdl/1959.1/8123.
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Booman, Richard Albert 1957. "DETERMINATION OF LOSS MECHANISMS IN LONG RANGE SURFACE PLASMON MODES." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/275490.
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STEIJN, KIRK WILLIAM. "COUPLING AND PROPAGATION OF SURFACE PLASMONS IN THE FAR-INFRARED (NEAR-MILLIMETER WAVES, SUB-MILLIMETER WAVES)." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183973.
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This work describes a study of the propagation properties of a modified surface plasmon mode, and of the coupling properties of that mode using a grating coupler. The surface plasmon, a polariton involving coupling of electromagnetic waves to the plasma oscillations of a metal, is modified by the application of a dielectric overlayer to the interface between the metal and air. In the far infrared region of the electromagnetic spectrum, the overlayer causes dramatic changes in several properties of the mode, which can be verified by measuring the propagation length of the mode. Measurements at a wavelength of 118.8 μm of the propagation length as a function of the thickness of a polycrystalline silicon overlayer on silver showed that the mode has the expected properties. They also indicated that the Drude model of the dielectric function of the silver is valid at 118.8 μm, even when using established Drude parameters, which are based on measurements in the visible and near infrared region of the electromagnetic spectrum. The coupling study measured the fundamental coupling parameters, also at a wavelength of 118.8 μm, for coupling via a grating between free-space waves and the surface plasmon, and measured the effect of the overlayer on these parameters. Efficient coupling was achieved, but a theoretical treatment of the coupling system proved to be beyond the scope of first-order grating-coupler theory. This was true despite the fact that the grating amplitude was a small fraction of the wavelength, a common criterion for the application of such a theory. Several possible reasons for the breakdown of the theory were considered, but definite answers require additional experiments. The most prominent possibilities are the shape factor, and the depth of the grating compared to the penetration depth of the fields into the metal. Though not all the data is completely explained, the studies herein demonstrate that the overlayer eliminates many of the deficiencies which limit the generation and control of far-infrared surface plasmons.
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Wang, Tao. "Excitation électrique de plasmons de surface avec un microscope à effet tunnel." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00868784.
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Pour la première fois, en associant un microscope à effet tunnel (STM) et un microscope optique inversé,nous avons imagé les plasmons de surface excités électriquement sur un film d'or avec la pointe d'un STM.Par microscopie de fuite radiative, en observant l'image de l'interface air/or et celle du plan de Fourierassocié, nous avons distingué les plasmons propagatifs des plasmons localisés sous la pointe. Les plasmonspropagatifs sont caractérisés par une distance de propagation et une direction d'émission en accord aveccelles de plasmons propagatifs créés par excitation laser sur des films d'or de mêmes épaisseurs. Les fuitesradiatives des plasmons localisés s'étalent jusqu'à l'angle maximum d'observation. Plasmons propagatifs etlocalisés ont une large bande spectrale dans le visible. Si la pointe est plasmonique (en argent), lesplasmons localisés ont une composante supplémentaire due au couplage associé. Pour différents types depointe, nous avons déterminé les intensités relatives des plasmons localisés et propagatifs. Nous trouvonsque chaque mode plasmon (propagatif ou localisé) peut être préférentiellement sélectionné en modifiant lematériau de la pointe et sa forme. Une pointe en argent produit une intensité élevée de plasmons localisés,tandis qu'une pointe fine de tungstène (rayon de l'apex inférieur à 100 nm) produit essentiellement desplasmons propagatifs. Nous avons étudié la cohérence spatiale des plasmons propagatifs excités par la pointe du STM. Avec un film d'or opaque (épaisseur 200 nm) percé de paires de nanotrous nous avons réalisé une expérienceanalogue à celle des fentes d'Young. Des franges d'interférences sont observées. La mesure de leurvisibilité en fonction de la distance des nanotrous donne une longueur de cohérence des plasmons de 4.7±0.5 μm. Cette valeur, très proche de la valeur 3.7± 1.2 μm déduite de la largeur de la distribution spectraledes plasmons, indique que l'élargissement spectral des plasmons propagatifs est homogène.Nous avons aussi étudié la diffusion des plasmons propagatifs excités par la pointe du STM par desnanoparticules d'or déposées sur un film d'épaisseur 50 nm. Nous observons une diffusion élastique et unediffusion radiative. Des franges d'interférences sont observées dans la région d'émission lumineuseinterdite du plan de Fourier, dont la période est inversement proportionnelle à la distancepointe-nanoparticule d'or avec un facteur de proportionnalité égal à la longueur d'onde moyenne desplasmons. Il y a donc interférence entre la radiation des plasmons localisés et la radiation provenant de ladiffusion des plasmons propagatifs sur les nanoparticules d'or. Ceci indique que les plasmons localisés etpropagatifs excités électriquement par la pointe du STM sont différentes composantes du plasmon uniqueproduit par effet tunnel inélastique avec la pointe du STM. Ces résultats originaux sur les plasmons créés sur film d'or par un effet tunnel inélastique localisé à l'échelle atomique (i) élargissent la compréhension du processus et (ii) offrent des perspectives intéressantes pour une association de la nanoélectronique et de la nanophotonique.
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Legay, Guillaume. "Analyse locale des sensibilités des lectures angulaires, spectroscopiques et ellipsométriques de la Résonance des Plasmons de Surface en vue de la miniaturisation des biocapteurs optiques." Phd thesis, Université de Bourgogne, 2006. http://tel.archives-ouvertes.fr/tel-00115725.
Full textAbstract:
Les puces à ADN, dont la détection est réalisée par fluorescence, ont démontré leur efficacité pour l'identification du génome depuis plusieurs années. Cependant, si on s'intéresse à l'analyse fine des interactions mises en jeu, c'est à dire visualiser en temps réel la cinétique de l'interaction, le marquage est susceptible de changer la distribution de charges et par la même de modifier l'affinité des sites de reconnaissance. Parmi les approches s'affranchissant du marquage fluorescent, notre choix s'est porté sur une détection optique, par ellipsométrie spectroscopique et / ou par la lecture de la résonance des plasmons de surface (RPS), des interactions, présentant le compromis le plus intéressant entre sensibilité et capacité de miniaturisation. Ces techniques optiques reposant sur la mesure couplée de l'épaisseur et des indices optiques de la couche adsorbée. Dans une première étape, la détermination statistique par Microscopie à Force Atomique de microstructures lithographiées et fonctionnées par des monocouches biomimétiques a permis d'estimer les variations d'épaisseurs nanométriques induites par l'adsorption des molécules étudiées. Si l'ellipsométrie spectroscopique présente une très grande sensibilité ex situ à l'indice optique, l'étude angulaire de réflectivité RPS s'avère être la technique optique la plus sensible en milieu liquide. Nous avons montré, par ailleurs que la lecture spectroscopique du déphasage de la réflectivité RPS est 100 x plus sensible que l'étude angulaire et permet de déterminer séparément les épaisseurs, le modèle d'indices optiques (gradient, fraction volumique) de la couche biologique.
Le passage d'une analyse monocapteur à une lecture multicapteurs a été étudié par deux modes de microscopies RPS :
- l'imagerie en champ lointain par CCD permet outre la rapidité d'acquisition, d'intégrer 1 000 capteurs / cm2
- la microscopie spectroscopique ellipsométrique à balayage, compte de tenu de la convolution du faisceau incident avec la surface microstructurée est limitée à 256 capteurs / cm2 mais présente l'avantage d'acquérir localement un spectre qui servira à une analyse paramétrique (indices optiques, fraction volumique, épaisseur).
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Canneson, Damien. "Modification de l'émission d'un nanocristal semi-conducteur individuel de CdSe-CdS à l'aide de nanostructures métalliques." Phd thesis, Université de Versailles-Saint Quentin en Yvelines, 2013. http://tel.archives-ouvertes.fr/tel-00911775.
Full textAbstract:
Les nanocristaux semi-conducteurs sont des objets de dimensions nanométriques aux niveaux d'énergie quantifiés. Grâce à leurs propriétés de fluorescence, ils trouvent des applications dans des domaines aussi variés que la biologie, l'opto-électronique ou l'optique quantique. Pour toutes ces applications, un contrôle de leurs propriétés d'émission est primordial. Dans ce cadre, après une étude fine de leurs propriétés d'émission à température cryogénique, nous nous sommes intéressés à leur couplage avec les plasmons de couches d'or désordonnées. Nous montrons alors la possibilité de supprimer efficacement les fluctuations d'intensité d'émission, d'accélérer drastiquement l'émission de photons et de créer des cascades bi-excitoniques.
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Zhang, Yinping. "Contribution to Photochemical Imaging of Complex Plasmonic Fields." Thesis, Troyes, 2017. http://www.theses.fr/2017TROY0041.
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Les oligomères plasmoniques sont des assemblages couplés en champ proche de nanoparticules métalliques. Tant leurs spectres de diffusion / absorption que la distribution spatiale du champ électromagnétique peut être adaptés par l'hybridation des modes plasmoniques oligomères par des particules individuelles. Un tel contrôle sur la distribution de champ ouvre de nouvelles voies pour délivrer la lumière à une échelle de sous-longueur profonde dans des endroits ciblés (points chauds). Cependant, le contrôle actif des points chauds dans les oligomères plasmoniques et leur observation dans le champ proche sont très difficiles. Dans cette thèse, nous proposons d'utiliser un processus d'absorption à deux photons dans le proche infrarouge photosensible afin d'imprimer à partir du champ lointain la distribution du champ proche autour de la nanoantenne trimère linéaire, de la nanoantenne trimère triangulaire et de la nanoantenne dimère bowtie. Ce travail montre que les modes de liaison et d'écartement anti-liaison sous ces oligomères plasmoniques simples peuvent être excités sélectivement par un contrôle à distance sous l'angle de l'incident et de l'état de polarisation de la lumière, conduisant à des emplacements contrôlés des points chauds. L'absorption de deux photons par un photopolymère contenant de l'azobenzène s'avère être une approche fiable pour étudier les champs plasmoniques confinés dans le proche infrarouge avec une résolution de 20 nmPlasmonic oligomers are near-field coupled assemblies of metallic nanoparticles. Both their scattering/absorption spectra and the spatial distribution of the electromagnetic field can be tailored through the hybridization of plasmonic modes hosted by individual particles. Such a control on the field distribution open new routes to deliver light at a deep subwavelength scale in targeted locations (“hot spots”). However, active control of hot spots in plasmonic oligomers and their observation in the near field are highly challenging. In this thesis, we propose to use a two-photon absorption process in photosensitive azobenzene-containing polymer in the near infrared to imprint from the far field the near field distribution around linear trimer nanoantenna, triangle trimer nanoantenna and bowtie dimer nanoantenna, respectively. This work shows that bonding and anti-bonding gap modes under these simple plasmonic oligomers can be selectively excited by remotely controlled through the angle of incident and the polariztion state of light, resulting in controlled hot spot locations. Two-photon absorption by azobenzene-containing photopolymer turns out to be a reliable approach for investigating confined plasmonic fields in the near infrared with a 20 nm resolution
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Wang, Huan. "Modeling of the plasmon resonance of metallic nanopaticles embedded in liquid crystal." Thesis, Troyes, 2014. http://www.theses.fr/2014TROY0004/document.
Full textAbstract:
Les nanoparticules métalliques ont des propriétés optiques uniques, dont le contrôle et l'optimisation ont un intérêt grandissant tant pour la recherche fondamentale qu'appliquée. Une propriété spectaculaire de ces nanoparticules est la résonance plasmon de surface localisé, qui est une conséquence des oscillations des électrons libres à l'interface métal/diélectrique.La position spectrale de la résonance plasmon est largement dépendante de la géométrie des nanoparticules, mais aussi de la constante diélectrique du milieu environnant. Un moyen pour contrôler cette résonance consiste donc à faire varier l'indice du milieu qui entoure les nanostructures. Les cristaux liquides nématiques sont un excellent moyen pour modifier et contrôler la résonance plasmon. En effet, par rotation des molécules du cristal liquide on peut induire un changement d'indice qui se traduit par un changement de la réponse optique des nanostructures. L'objectif de la thèse est de simuler des réseaux de nanoparticules d'or, dans un cristal liquide nématique afin de prédire l'influence de l'orientation du CL sur les propriétés optiques de ces nanostructures. Le formalisme numérique utilisé est basé sur la méthode des différences finies dans le domaine temporel (FDTD). Nous avons pris en compte les phénomènes d'ancrage des molécules aux interfaces avec la cellule contenant les cristaux liquides et les structures métalliques, et comparé les résultats avec le cas d'une orientation uniforme des molécules dans la cellule. La possibilité d'avoir une double résonance a été étudiée, ainsi que les gain SERS associés à ces structures spécifiquesMetal nanoparticles have unique optical properties, the control and optimization have a growing interest in fundamental research as same as applied research. A spectacular property of these nanoparticles is the localized surface plasmon resonance ( LSPR ), which is a consequence of the oscillations of free electrons at the interface between metal and dielectric.The spectral position of the plasmon resonance is largely dependent on the geometry of the nanoparticles, but also on the dielectric properties of the surrounding medium. It implies that the variation of the index of the medium surrounding the metallic nanostructures can control the LSPR resonance. Nematic liquid crystals are a great way to modify and control the plasmon resonance. Indeed, rotation of the liquid crystal molecules can induce a change in refractive index which results in a change in the optical response of the nanostructures. The aim of the thesis is to simulate arrays of gold nanoparticles in a nematic liquid crystal in order to predict the influence of the orientation of the LC molcules on the optical properties of these nanostructures. Numerical method we used is based on the finite difference time domain ( FDTD ) method. We have considered anchoring effects of molecules at the interfaces between the cell containing the liquid crystal and the substrates. And the results are compared with the case of uniform orientation of the LC molecules in the cell. The possibility of having double resonances was studied as well as the Surface Enhanced Raman Scattering (SERS ) gain associated with these specific structures