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Loss compensation in a plasmonic nanoparticle arrayMiller, Shannon Marie 20 November 2013 (has links)
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
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MODELING PULSE PROPAGATION IN LOSS COMPENSATED MATERIALS THAT EXHIBIT THE NEGATIVE REFRACTIVE INDEX PROPERTYKENNEDY, BRIDGET ROSE January 2009 (has links)
Rapid development in nanofabrication has led to the design of new materials with very unusual properties. The exhibition of negative and zero indices of refraction are among the most striking properties of these materials, which have become the focus of intensive research worldwide. The potential for applications that is possible due to the new light manipulation capabilities of these materials has been the driving force behind this research. Most of the research in this field has primarily been experimental while the theoretical studies have mainly been limited to computer modeling, which in itself is a challenging problem. This research requires considerable computational resources and the development of new computer algorithms.The origin of the unusual properties in these materials comes from the combination of dielectric host materials with metallic nanosructures. These materials are often referred to as nanocomposite metamaterials. The plasmonic resonance in properly engineered metallic nanostructures gives rise to the resonant interaction of the incident electromagnetic field with metamaterials in such a way as to stimulate a magnetic permeability and an electric permittivity with negative real parts. The resonant nature of this phenomenon leads to considerable losses in metamaterials, which has made the study of loss compensation one of the key subjects in this field.The two techniques of loss compensation in metamaterials are considered in this dissertation. One of these techniques consists of doping the host material with active atoms. In the second technique, loss compensation is achieved by embedding these active atomic inclusions directly into the nanostructures. This dissertation presents the derivation of the systems of governing equations and studies the coherent pulse amplification for both cases.
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Compensating for Unreliable Communication Links in Networked Control SystemsHenriksson, Erik January 2009 (has links)
<p>Control systems utilizing wireless sensor and actuator networks can be severely affectedby the properties of the communication links. Radio fading and interferencemay cause communication losses and outages in situations when the radio environmentis noisy and low transmission power is desirable. This thesis proposes amethod to compensate for such unpredictable losses of data in the feedback controlloop by introducing a predictive outage compensator (POC). The POC is a filter tobe implemented at the receiver sides of networked control systems where it generatesartificial samples when data are lost. If the receiver node does not receive thedata, the POC suggests a command based on the history of past data. It is shownhow to design, tune and implement a POC. Theoretical bounds and simulationresults show that a POC can improve the closed-loop control performance undercommunication losses considerably. We provide a deterministic and a stochasticmethod to synthesize POCs. Worst-case performance bounds are given that relatethe closed-loop performance with the complexity of the compensator. We also showthat it is possible to achieve good performance with a low-order implementationbased on Hankel norm approximation. Tradeoffs between achievable performance,communication loss length, and POC order are discussed. The results are illustratedon a simulated example of a multiple-tank process. The thesis is concludedby an experimental validation of wireless control of a physical lab process. Herethe controller and the physical system are separated geographically and interfacedthrough a wireless medium. For the remote control we use a hybrid model predictivecontroller. The results reflect the difficulties in wireless control as well as theyhighlight the flexibility and possibilities one obtains by using wireless instead of awired communication medium.</p> / VR, SSF, VINNOVA via Networked Embedded Control Systems, EU Sixt Framework Program via HYCON and SOCRADES
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Notion et Traitement des soldes déficitaires en droit fiscal. Aspects nationaux et internationaux (y compris les aspects de droit européen)Richelle, Isabelle 08 December 1998 (has links)
Notion de revenu et de perte
Compensation des pertes et annualité de l'impôt
Compensation des pertes et territorialité de l'impôt
Analyse comparative des législations belge, française et néerlandaise
Notion of income and loss
Loss compensation and principle of annuality
Loss compensation and territoriality
Comparative analysis of the Belgian, French and Dutch tax legislations
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Compensating for Unreliable Communication Links in Networked Control SystemsHenriksson, Erik January 2009 (has links)
Control systems utilizing wireless sensor and actuator networks can be severely affectedby the properties of the communication links. Radio fading and interferencemay cause communication losses and outages in situations when the radio environmentis noisy and low transmission power is desirable. This thesis proposes amethod to compensate for such unpredictable losses of data in the feedback controlloop by introducing a predictive outage compensator (POC). The POC is a filter tobe implemented at the receiver sides of networked control systems where it generatesartificial samples when data are lost. If the receiver node does not receive thedata, the POC suggests a command based on the history of past data. It is shownhow to design, tune and implement a POC. Theoretical bounds and simulationresults show that a POC can improve the closed-loop control performance undercommunication losses considerably. We provide a deterministic and a stochasticmethod to synthesize POCs. Worst-case performance bounds are given that relatethe closed-loop performance with the complexity of the compensator. We also showthat it is possible to achieve good performance with a low-order implementationbased on Hankel norm approximation. Tradeoffs between achievable performance,communication loss length, and POC order are discussed. The results are illustratedon a simulated example of a multiple-tank process. The thesis is concludedby an experimental validation of wireless control of a physical lab process. Herethe controller and the physical system are separated geographically and interfacedthrough a wireless medium. For the remote control we use a hybrid model predictivecontroller. The results reflect the difficulties in wireless control as well as theyhighlight the flexibility and possibilities one obtains by using wireless instead of awired communication medium. / VR, SSF, VINNOVA via Networked Embedded Control Systems, EU Sixt Framework Program via HYCON and SOCRADES
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Synthèse, assemblage et caractérisation de matériaux plasmoniques pour une application aux métamatériaux / Synthesis, assembly and characterization of plasmonic material for metamaterials applicationsCoutant, Christophe 16 December 2014 (has links)
Les métamatériaux sont des matériaux artificiels présentant des propriétés que l’on neretrouve pas dans les matériaux naturels. Il s’agit en général de matériaux compositesconstitués de résonateurs dont la réponse intense permet l’obtention de propriétés uniques.Cette thèse est consacrée à la fabrication et à l’étude de métamatériaux électromagnétiquespour une utilisation dans la gamme de fréquences du spectre visible. Nos matériaux sont desassemblages denses de nanoparticules coeur écorce. Le coeur métallique d’or présente unerésonance plasmon dans le visible et l’écorce de silice permet de contrôler les couplagesinterparticulaires. Les matériaux sont réalisés par une méthode dérivée de la technique deLangmuir-Blodgett et par microévaporation. Les propriétés optiques des matériaux sontétudiées par ellipsométrie spectroscopique. Nous avons mis en évidence la présence d’uncouplage fort avec le substrat de silicium permettant l’obtention d’indice réfraction n < 0,5dans le cas du système le plus fortement couplé. Nous avons décrit un phénomèned’extinction topologique pouvant être mis à profit pour la fabrication de capteurs ultrasensibles.Nous avons également synthétisé des nanoparticules présentant un coeur de silicechargé de molécules fluorescentes encapsulé d’une écorce d’or dont l’étude a permis unemeilleure compréhension du phénomène de compensation de perte. / Metamaterials are artificial materials exhibiting novel properties that are not found in naturalmaterials. Metamaterials are usually composite materials which contain artificial resonatorswhose intense response generates unique properties. This thesis is dedicated to the fabricationand characterization of electromagnetic metamaterials which are designed to be used atoptical frequency. Our materials are dense assemblies of core-shell nanoparticles. Corenanoparticles exhibit a plasmon resonance in the visible and the silica shell is used to controlthe interparticle coupling. The materials are made by a method derived from the Langmuir-Blodgett technique and by microevaporation. The optical properties of the materials werestudied by spectroscopic ellipsometry. We have demonstrated the presence of a strongcoupling with the silicon substrate which allows for a refractive index value of n <0.5, in thecase of the most coupled system. We have also described a topological extinctionphenomenon that can be exploited for the production of ultra-sensitive sensors. Finally, wesynthesized silica nanoparticles containing fluorescent molecules that are encapsulated with agold shell whose study has allowed for a better understanding of loss compensationphenomenon.
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Plasmonic properties and applications of metallic nanostructuresZhen, Yurong 16 September 2013 (has links)
Plasmonic properties and the related novel applications are studied on various
types of metallic nano-structures in one, two, or three dimensions. For 1D nanostructure,
the motion of free electrons in a metal-film with nanoscale thickness is confined in
its normal dimension and free in the other two. Describing the free-electron motion at
metal-dielectric surfaces, surface plasmon polariton (SPP) is an elementary excitation
of such motions and is well known. When further perforated with periodic array of
holes, periodicity will introduce degeneracy, incur energy-level splitting, and facilitate
the coupling between free-space photon and SPP. We applied this concept to achieve
a plasmonic perfect absorber. The experimentally observed reflection dip splitting
is qualitatively explained by a perturbation theory based on the above concept. If
confined in 2D, the nanostructures become nanowires that intrigue a broad range of
research interests. We performed various studies on the resonance and propagation
of metal nanowires with different materials, cross-sectional shapes and form factors,
in passive or active medium, in support of corresponding experimental works. Finite-
Difference Time-Domain (FDTD) simulations show that simulated results agrees well
with experiments and makes fundamental mode analysis possible. Confined in 3D,
the electron motions in a single metal nanoparticle (NP) leads to localized surface
plasmon resonance (LSPR) that enables another novel and important application:
plasmon-heating. By exciting the LSPR of a gold particle embedded in liquid, the
excited plasmon will decay into heat in the particle and will heat up the surrounding
liquid eventually. With sufficient exciting optical intensity, the heat transfer from NP
to liquid will undergo an explosive process and make a vapor envelop: nanobubble.
We characterized the size, pressure and temperature of the nanobubble by a simple
model relying on Mie calculations and continuous medium assumption. A novel
effective medium method is also developed to replace the role of Mie calculations.
The characterized temperature is in excellent agreement with that by Raman scattering.
If fabricated in an ordered cluster, NPs exhibit double-resonance features and
the double Fano-resonant structure is demonstrated to most enhance the four-wave
mixing efficiency.
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