Les structures optiques diffractives sous forme d’hologramme de sécurité sont largement employées contre la falsification et la contrefaçon.Elles sont présentent sur les billets de banque, les documents de voyage et d’identité, etc. Leurs techniques de fabrication sont de plus en plus accessibles, augmentant les risques de fraudes et la concurrence sur le marché des hologrammes de sécurité. Pour endiguer les fraudes et gagner des parts de marché, il faut innover. Ces travaux de thèse de doctorat s’articulent autour du développement de structures optiques diffractives multiéchelles innovantes. Ces structures diffractives multiéchelles sont la combinaison de structures diffractives microscopiques permettant la mise en forme de la lumière incidente avecdes structures nanoscopiques qui permettent la création d’effets colorés. Ces travaux accordent une grande place au développement de la technique de photolithographie multiniveaux par écriture directe massivement parallèle. Ils abordent également le développement d’un modèle hybride permettant de simuler physiquement le comportement des structures diffractives (notamment de nos structures multiéchelles) en temps réel. Ce rendu en temps réel est possible grâce à l’utilisation du processeur graphique (GPU) au travers d’OpenGL et des programmes Shader, ainsi qu’avec l’utilisation de données précalculées. Le développement de ces structures multiéchelles permet la création et la commercialisation de nombreux nouveaux effets visuels, ce qui participe aux doubles objectifs de contrer les fraudes et de gagner en part de marché. / Diffractive optical structures on the fon of security holograms are widely used against forgery and counterfeiting. They are present on banknotes, travel and identity documents, etc. Their manufacturing techniques are becoming more and more accessible, increasing the risk of fraud and competition in the security hologram market. To stem fraud and gain marketshare, hologram procedures must innovate continously. This Ph.d focuses on the developmentof innovative multi-scale diffractive optical structures. These multi-scale diffractive structures result from combination of microscopic diffractive structures that shape the incident light and nanoscopic structures that generate colored effects. This work places emphasis on the development of the massively parallel-direct-write greyscale photolithography fabrication process. We also discuss the development of an hybrid model for physically simulating the behaviour of diffractive structures (especially our multiscale structures) in real time. This real time rendering is possible thanks to the use of the graphical processor unit (GPU) through OpenGL and Shader programs, as well as the use of precomputed data. The development of these multiscale structures has led to the creation and commercialisation of many new visual effects and contributed to the dual objectives of counter fraud and gain market share.

Technical advancements in 3D projection has recently made presentation of holographic images possible by using self-contained devices. Instead of using a screen to present objects, glasses like Microsoft HoloLens can render objects that appear as holograms around the user. SAAB Defence and Security are evaluating if this new technology can complement their command and control system 9LV Combat Management System. This degree project is a study of the technical possibilities and limitations of introducing holographic display of sonar tracks used for detecting submarines or sea mines. The project was started with a background study into what methods are available to render 3D underwater terrain. A basic hologram representing a map of littoral terrain was constructed and simulated sonar tracks from the command and control system was mapped into the terrain. Implementation of the application was done using the Unity 3D game engine that has built in support for the HoloLens. Performance evaluation was done using Unity3D profiler that is an extensive application evaluation tool that maintain overhead to a minimum. An evaluation of HoloLens usage onboard two different boats was done to conclude if the equipment can be used in the normal 9LV CMS operating environment. Results show that it is possible to successfully use holographic display for sonar tracks, but due to limited processing power of the HoloLens terrain detail will be reduced. Holograms are orientated by combining camera spatial mapping and an inertial measurement unit. Usage tests onboard a vessel indicates that holograms will unexpectedly move and the HoloLens will loose spatial mapping due to acceleration forces caused by seastate. / Tekniska framsteg inom presentation av 3D-objekt har nyligen möjliggjort användning av hologram presenterade med portabel utrustning. Istället för att använda en vanlig skärm kan glasögon, som Microsoft HoloLens, rendera objekt som användaren upplever i sin omgivning som hologram. SAAB Defence and Security utvärderar om den nya teknologin kan användas som ett komplement till deras ledningssystem 9LV Combat Management System. Det här examensarbetet är en studie av de tekniska möjligheter och begränsningar som finns för att bygga en applikation som visar sonar-information som ett hologram, främst att användas för ubåtsjakt och upptäckt av sjöminor. Projektet inleddes med en bakgrundsstudie om vilka metoder som finns tillgängliga för att rendera en 3D-karta av en havsbotten. En enkel applikation med en karta som föreställer en del av skärgården tas fram med simulerad sonar-information från ledningssystemet inlagt i kartan. Implementationen av applikationen gjordes med spelmotorn Unity3D som har inbyggt stöd för Microsoft HoloLens. Prestandautvärdering genomfördes genom att använda ett inbyggt profileringsverktyg i Unity3D som har liten påverkan på prestandan. Utvärdering av möjlig användningsmiljö gjordes genom att testa utrustningen ombord på två olika båtar för att avgöra om HoloLens kan användas i 9LV CMS normala operativa förhållanden. Resultaten visar att det är möjligt att använda holografisk visning för sonar-data men upplösningen av terrängen för kartan är något låg på grund av den begränsade beräkningskraften i Microsoft HoloLens. Hologram i Microsoft HoloLens orienteras genom att kombinera en djupseende kamera med en intern referensenhet. Användningstester ombord på båt visar på att vid accelerationer som uppkommer av sjöhävning tappar HoloLensen rumsuppfattningen tillfälligt och stoppar renderingen av hologrammet.

Les auteurs contemporains, des plasticiens aux réalisateurs de blockbusters, créent des images où le réel et le virtuel semblent de la même étoffe. Leurs films, vidéos et installations exposent un monde qui émerge de l’immatérialité des écrans.À la différence des images qui procèdent de l'imprégnation de la lumière réelle sur des surfaces photosensibles, les simulacres numériques résultent du langage binaire. Ils correspondent à du code informatique qui transforme l’image en une somme de données.Dès lors, ceux-ci entraînent-ils une mutation de notre rapport à l’image ? En quoi induisent-ils une nouvelle perception des représentations artistiques où prime l’apport d’une subjectivité ?Les simulacres numériques apparaissent après des millénaires d’images qui relèvent de l’ontologie et entretiennent un lien sensible avec le réel. Le spectateur ayant besoin de se projeter dans ce qui emprunte à sa nature et ce qui interroge ses aspirations, ses sentiments comme ses croyances, il attend de la simulation numérique la même capacité d’incarnation et de transfiguration que les autres moyens d’expression.Entrelaçant la tradition et le contemporain, cette recherche analyse l’éloquence sensible du simulacre numérique au défi du vivant dans le cinéma et les arts plastiques des années 2000-2010 selon les concepts de présence, représentation et simulation.Comment le numérique actualise-t-il des codes culturels et esthétiques hérités de l’histoire de l’art ? Cette recherche tente de comprendre la nature et le sens des simulacres numériques du vivant en tant qu’ils conjuguent l’incorporel synthétique à l’argument ontologique. / The contemporary authors, from visual artists to blockbusters’ directors, create images where the real and the virtual seem from the same cloth. Theirs movies, videos and installations show a world which emerges from the immateriality of the screens.Unlike images which are the result of the impregnation of the actual light on photosensitive surfaces, digital simulacra stem from binary language. They are made of pure computer code that can transform the image into a sum of data.Therefore, will the digital simulacra change our relationship to images? How do these digital sham images induce a new perception of artistic performances where subjectivity and its contributions are the prime factors?We are confronted with these digital simulacra of images after millennia of imagery that relate from ontology and that maintain a significant link with reality. The viewer, having the need to project himself into something that borrows from his nature and that questions his aspirations, his feelings as well as his beliefs, expects from the digital simulation the same capacity for incarnation and transfiguration that he experiences from others means of expression.Confronting and intertwining the traditional and the contemporary, this research analyses the sensitive eloquence of digital simulacra and how they face the challenge of real life, through film and in visual arts over the decade 2000-2010, based on the concepts of presence, representation and simulation.How do the various uses of digital technology force us to update the cultural and aesthetic codes that we inherited from Art history? Thus, this research attempts to understand the substance and the meaning of the digital pretence of life, which combines the synthetic intangible with an ontological argument.

Wavelength division multiplexing (WDM) is essential for further enhancement of the transmission capacities of optical telecommunication systems. Key devices in WDM networks are multiplexing/demultiplexing components, which enable the combination/separation of several carrier waves with different wavelengths for the purpose of simultaneous transmission through one optical fibre. These components can be realized using Bragg diffraction from volume holographic gratings. Especially reflection holograms provide a pronounced wavelength selectivity which makes them attractive for free-space WDM applications. Holograms can be stored permanently in photorefractive lithium niobate crystals by the method of Thermal Fixing. Heating of the crystal during or after the recording process and subsequent development by homogeneous illumination at room temperature create nonvolatile holograms. The recording and development processes of Thermal Fixing in iron- and copper-doped lithium niobate crystals were investigated. Macroscopic Gaussian-shaped intensity patterns were used to analyse the origin of the fixing mechanism. Spatially resolved absorption measurements were performed to determine the concentration profiles of electron traps (Fe II/III) and protons. Results of computer simulations were compared with experimental results, which showed that protons can be found to work as compensators during hologram recording at temperatures around 180 degree C. Nevertheless thermal fixing without protons was possible, another compensation mechanism stood in. The obtained refractive-index changes were due to the electro-optic effect, other contributions could be neglected. With this detailed knowledge about thermal fixing, a two-channel demultiplexing unit was built by superposition of two thermally fixed reflection holograms in an iron-doped lithium niobate crystal. For this purpose a special two-beam interference setup with precisely adjustable writing angles was arranged in a vacuum chamber to eliminate thermally induced phase disturbances of the holographic recording procedure. Continuous development of the holograms by incoherent light was necessary. In the dark, the enhanced dark conductivity of the crystal used gave rise to a hologram degradation within about one day. Large diffraction efficiencies were attained (intensity losses between 2.3 and 5.2 dB only) uilizing crystals with high-quality polished surfaces. The crosstalk supression of the realized demultiplexer was > 25 dB, which is comparable with the performance of other multiplexing techniques like fibre Bragg gratings or arrayed-waveguide gratings. The low polarization dependence of the demultiplexer can be improved by superposition of two holograms for each channel.

Made available in DSpace on 2016-03-15T19:34:24Z (GMT). No. of bitstreams: 1 Leandro Moreira Valente Barbas.pdf: 3080773 bytes, checksum: 5224fe793510ae5cce0c2781893d8c66 (MD5) Previous issue date: 2015-08-05 / Fundo Mackenzie de Pesquisa / The scenario of tough competition, typical of any market economy, stimulates the creativity of its players when building brand identities. The search for signs that separate from the traditional model based on a visual static mark, classified as a sole design, word or mixed mark is increasingly common. Law cannot remain idle in witnessing this scenario, since those new distinctive signs have their own particularities that are not contemplated by the Brazilian Industrial Property Law. The protection of the consumer market, of free competition and even of the owners private property of the signs themselves depend necessarily on having clear answers from the Law regarding the issue. Otherwise, the trademark system may become unstable. Therefore, this work aims at defining basic concepts regarding the theme and analyzing the main legal issues related to nontraditional marks, having international experiences on the matter as a basis. / O cenário de acirrada competição típico de qualquer economia de mercado estimula a atividade criativa de seus participantes quando da construção de identidades marcárias. É cada vez mais constante e comum a busca por sinais que fogem ao modelo tradicional de marca visual estática, figurativa, mista ou nominativa. Estes sinais recebem o nome geral de marcas não tradicionais . O Direito não pode aí quedar-se inerte, uma vez que estes novos sinais distintivos têm peculiaridades próprias que fogem, em boa medida, à sistemática determinada pela Lei de Propriedade Industrial. Logo, a proteção do mercado consumidor, da livre concorrência e mesmo da propriedade privada dos titulares dos sinais passam necessariamente por uma obtenção de respostas claras do Direito neste tema, sob pena de instabilizar-se o sistema marcário. Esta obra tem o objetivo de delinear conceitos básicos sobre o tema das marcas não tradicionais e analisar as principais problemáticas jurídicas envolvidas, baseando-se em experiências internacionais na matéria.

We develop a theory of vectorial wave coupling in cubic photorefractive crystals placed in an alternating ac-field to enhance the nonlinear response. First we analytically and numerically investigate the dependences of the first Fourier harmonics of the space-charge field, induced in an AC-biased sillenite crystal by a light-interference pattern, on the light contrast m. The data obtained was used to extend the vectorial beam-coupling theory on the whole contrast region. In particular, we proved in the general case that despite of essential differences between thediffusion and AC nonlocal responses the later keeps the light interference fringes straight during the interaction. This fundamental feature allows, under certain restrictions, to reduce the nonlinear problem of vectorial coupling to the known linear problem of vectorial Bragg diffraction from a spatially uniform grating, which admits an exact solution. As a result, the nonlinear vectorial problem can be effectively solved for a number of practically important cases.The developed theory was applied to describe the transformation of a momentary phase changes of one of the input beams into the output intensity modulation (so-called grating translation technique). In contrast to the previous studies, we take into account the change of the space-charge field amplitude across the crystal (the coupling effects). The theory developed is employed to optimize the conditions for the linear signal detection under polarization filtering for the transverse and longitudinal optical configurations. We also analyze the possibility of the linear detection without polarization filtering.Illumination of AC-biased photorefractive BTO crystals with a coherent light beam results in development of strong nonlinear scattering. We investigate the angular and polarization characteristics of the scattered light for the diagonal optical configuration and different polarization states of the pump.