Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Nesta tese são apresentadas a medida da taxa de produção de eventos difrativos e a extração da função de estrutura do antipróton para eventos de difração simples. A análise aqui apresentada é baseada em dados do detector DØ no Tevatron/Fermilab, colisor de prótons-antiprótons à energia de centro de massa de 1.96 TeV. A seleção de eventos difrativos é feita através de intervalos de rapidez - região do detector desprovida de partículas - determinados através da deposição de energia nas células do calorímetro DØ. A função de estrutura obtida nessa análise é comparada com resultados existentes dos experimentos H1 e CDF. / In this thesis we present a measurement of the diffractive to non-diffractive production rate and the extraction of the antiproton diffractive structure function. The analysis presented uses data from the DØ proton-antiproton collider at Tevatron/Fermilab with = 1.96 TeV. The data sample was selected using rapidity gap signatures determined through the sum of energy depositions in the DØ calorimeter cells. The measurements were performed on 0.19 pb-1 of Run IIa DØ data. The results are compared to H1 and CDF results."

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Nesta tese são apresentadas a medida da taxa de produção de eventos difrativos e a extração da função de estrutura do antipróton para eventos de difração simples. A análise aqui apresentada é baseada em dados do detector DØ no Tevatron/Fermilab, colisor de prótons-antiprótons à energia de centro de massa de 1.96 TeV. A seleção de eventos difrativos é feita através de intervalos de rapidez - região do detector desprovida de partículas - determinados através da deposição de energia nas células do calorímetro DØ. A função de estrutura obtida nessa análise é comparada com resultados existentes dos experimentos H1 e CDF. / In this thesis we present a measurement of the diffractive to non-diffractive production rate and the extraction of the antiproton diffractive structure function. The analysis presented uses data from the DØ proton-antiproton collider at Tevatron/Fermilab with = 1.96 TeV. The data sample was selected using rapidity gap signatures determined through the sum of energy depositions in the DØ calorimeter cells. The measurements were performed on 0.19 pb-1 of Run IIa DØ data. The results are compared to H1 and CDF results."

In this work, two distinct types of Diffractive Optical Elements (DOEs) are designed to laterally distribute the solar spectrum across multiple photovoltaic (PV) cells. Each PV cell receives a spectral band near its bandgap energy to maximize overall solar-to-electric conversion efficiency of the system. The first DOE is an off-axis volume holographic lens. Design parameters include lateral grating period and slant angle, index modulation, film thickness, and control of swelling and index modulation attenuation in the film development process. Diffraction efficiency across the holographic lens is simulated using Rigorous Coupled Wave Analysis (RCWA). A full system model is created, and non-sequential raytracing is performed. Performance is evaluated under AM 1.5 conditions and annual insolation in Tucson, AZ, and Seattle, WA. A proof-of-concept off-axis holographic lens is fabricated and its performance is measured to confirm the optical properties of this system. The second DOE is an algorithmically-designed freeform surface relief structure. The Gerchberg-Saxton design algorithm is expanded to consider multiple wavelengths, resulting in a Broadband Gerchberg-Saxton (BGS) algorithm. All design variables are evaluated in a parametric study of the algorithm. Several DOE designs are proposed for spectrum splitting, and two of these designs are fabricated and measured. Additional considerations, such as finite sampling of the discrete Fourier transform, fabrication error, and solar divergence are addressed. The dissertation will conclude with a summary of spectrum splitting performance of all proposed DOEs, as well as a comparison to ideal spectrum splitting performance and discussion of areas for improvement and future work.

Thesis (MSc)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Lasers are commonly used in the industry for various applications such as laser cutting, laser drilling, lithography, medical applications, surface cleaning and a myriad of other applications. In any application of a laser the beam properties are significant. In the paint removal application discussed in this thesis, the beam properties of the laser beam can have a large impact on the efficiency of the paint removal process. The pulse energy or the average output power of the laser is normally an important parameter in laser materials processing applications. The spatial profile or intensity distribution of the beam also has an influence on the process. The propagation of the laser beam from the laser to the working point is also significant in applying the laser beam to the material. In the ideal scenario one would like to control all the parameters of the laser in terms of the output, in energy or output power, the propagation of the laser beam and the intensity distribution of the beam. The process of laser-based paint removal is no different to this. In this process a TEA CO2 laser is used for the ablation of paint from a substrate. In this application high pulse energy is required from the laser together with good beam propagation properties for delivery of the beam over a long distance. For this application the multimode beam of the TEA CO2 laser can be applied for the paint removal. The multimode beam has sufficiently high pulse energy for the paint removal process, but is not suitable for propagating over long distances through a beam path with a finite aperture. Furthermore the multimode beam does not have a uniform energy intensity distribution. It would therefore be ideal if the TEA CO2 laser could be designed with a custom beam that has a uniform intensity distribution, high pulse energy and good beam propagation. These requirements lead to the study of flattened irradiance profile laser beams. In this thesis flattened irradiance profile beams in the form of Flattened Gaussian beams are investigated. The theory of the Flattened Gaussian profile as well as the propagation of the beam is investigated. Furthermore the generation of such a beam internally to the laser resonator is studied. In succession to this a custom laser resonator was designed and implemented on the TEA CO2 laser. The resulting Flattened Gaussian Beam was characterised and applied to the application of laser paint removal. It was finally shown that the Flattened Gaussian Beam could be successfully generated and applied with equal success in the application of laser paint removal. / AFRIKAANSE OPSOMMING: Lasers word algemeen in die industrie gebruik vir toepassings soos laser snywerk, laser boorwerk, litografie, mediese toepassings, oppervlakreiniging en verskeie ander. In enige toepassing van 'n laser is die eienskappe van die laserbundel van groot belang vir die proses. In die verf verwydering toepassing wat bespreek word in hierdie tesis het die bundel eienskappe 'n groot invloed op die effektiwiteit van die verf stropings proses. Die pulsenergie of uitset drywing van die laser is gewoonlik 'n belangrike parameter in 'n materiaalverwerkings toepassing. Die ruimtelike profiel of energie intensiteitprofiel van die bundel het ook 'n invloed op die proses. Die voortplanting van die bundel vanaf die laser na die werkspunt het ook 'n beduidende invloed op die toepassing van die laserbundel op die materiaal. In die ideale geval sal mens graag al die parameters van die laserbundel soos pulsenergie of drywing, die bundel voortplanting en energie intensiteitprofiel wil beheer. Die toepassing van die laser vir verfverwydering vereis ook die beheer van hierdie unieke parameters wat reeds genoem is. In hierdie proses is 'n TEA CO2 laser gebruik vir die verwydering van verf van 'n substraat. Die toepassing vereis hoë pulsenergie saam met goeie bundel voortplantingseienskappe vir lewering van die bundel oor lang afstande. Die multimode bundel van die laser kan gebruik word vir hierdie toepassing. Die multimode bundel bevat genoegsame energie vir die verfstropings proses maar is nie geskik vir voortplanting oor lang afstande deur 'n bundelpad wat 'n beperking op die bundel grootte het nie. Verder het die multimode bundel ook nie 'n uniforme energie intensiteitprofiel nie. Dit sou ideal wees as die TEA CO2 laser toegerus kon word met 'n toepassingsgerigte bundel wat hoë puls energie, goeie bundel voortplanting en 'n uniforme intensiteitprofiel het. Hierdie vereiste het gelei tot die studie van laserbundels met 'n uniforme plat energie intensiteitprofiel. In hierdie tesis word plat intensiteit bundels in die vorm van plat Gaussiese bundels ondersoek. Die teorie van plat Gaussiese bundels sowel as die voortplanting van hierdie bundels word hier ondersoek. Verder word die opwekking van hierdie bundels intern tot die laserresonator ook ondersoek. Na die ondersoek is daar oorgegaan in die ontwerp en implementering van 'n doelgemaakte resonator op 'n TEA CO2 laser. Die resonator het 'n plat Gaussiese bundel as uitset gelewer. Die bundel was gevolglik gekarakteriseer en aangewend in 'n verfstropings toepassing. Ten einde is daar getoon dat 'n plat Gaussiese bundel suksesvol opgewek en toegepas kon word.

This dissertation presents theoretical and experimental work on non-imaging diffractive optics. The new use of devices based on this work is shown and grouped by application. First, devices for telecommunications applications are described: volume reflection Bragg gratings were designed for wavelength division multiplexing (WDM) and optical code division multiple access (OCDMA) applications. Two devices based on reflection Bragg filters are presented in this work. Tunable phenanthrenquinone-doped poly(methyl methacrylate) (PQ-PMMA) edge illuminated Bragg filters were found to be wavelength selectable via the application of a constant stress, either in tension or compression, allowing for a wavelength tuning of ~4.5nm. Silica on silicon, multichannel parallel anti-symmetric waveguide Bragg gratings (AWBG) are theoretically demonstrated based on coupled mode theory, mode overlap with parallel gratings and previous experimental results with single channel AWBGs. These parallel AWBG devices are shown to be scalable, with the device length increasing as the number of parallel channels increases. Second, diffractive devices based on flexible, volume transmission holograms are presented and demonstrated for low level solar concentration in latitude mounted applications. The film, arrayed next to the solar cells, directs the incoming solar irradiance incident upon it towards the solar cell. These holograms are shown to work for both silicon and Copper Indium Gallium diSelenide (CIGS) solar cells. New solar holographic designs for non-latitude mounting applications are also shown for common photovoltaic materials. The holographic designs are based on approximate coupled wave analysis (ACWA), the latitude and mounting angle of the application, the spectral response of the photovoltaic material, and the seasonal and daily sun angle position. The simulation work suggests that holograms optimized for non-latitude mounted applications contribute proportionately more energy throughout the year than earlier latitude mounted hologram designs.

Detection of earth-size exoplanets using the astrometric signal of the host star requires sub-microarcsecond measurement precision. One major challenge in achieving this precision using a medium-size (< 2-m) space telescope is the calibration of dynamic distortions. A diffractive pupil can be used to generate polychromatic diffraction spikes in the focal plane, which encode the distortions in the optical system and may be used to calibrate astrometric measurements. The first half of this dissertation discusses the design and construction of a laboratory to test this concept. The main components of the system are a high stability star simulator, a diffraction limited off-axis optical system, and the data reduction algorithms to obtain the distortion map calibration. Currently, the laboratory is operational and first tests of distortion measurements have been done validating this concept to improve the astrometric accuracy of a telescope. The second part of this dissertation describes the use of the multi-laser guide star (LGS) system available at the 6.5 m MMT telescope to characterize GLAO performance and advance Laser Tomography Adaptive Optics (LTAO) technology. The system uses five range-gated and dynamically refocused Rayleigh laser beacons to sense the atmospheric wavefront aberration. Corrections are then applied to the wavefront using the 336-actuator adaptive secondary mirror of the telescope. So far, the system has demonstrated successful control of ground-layer aberration over a field of view (FoV) substantially wider than is delivered by conventional adaptive optics, yielding reduction in the width of the on-axis point-spread function from 1.07" to < 0.2" in H band. Both techniques can be combined to improve the astrometric accuracy of ground based telescopes, especially when using Multi-Conjugated Adaptive Optics (MCAO). A diffractive pupil can be used to calibrate the distortions induced by multiple Deformable Mirrors (DM), which is the main limitation to use this kind of AO system for high precision astrometric measurements.

This thesis presents a unique design for an infrared spectrometer based on a MEMS Binary Fresnel Zone Plate for the purpose of assessing the health of oil-impregnated high voltage (HV) equipment. It does so by measuring dissolved gases within it. These gases include carbon monoxide, carbon dioxide, methane, ethane, ethylene, and acetylene. These gases are currently measured using numerous technologies such as gas combustion, gas chromatography, photoacoustic spectroscopy, and FTIR spectroscopy. Each of these technologies have their advantages and disadvantages. The design presented in this thesis consists of an analysis of how the various Binary Zone Plate parameters affect its spectral resolution and transmission efficiency. Simulations show that increasing the number of zones and the focal length, as well as decreasing the aperture diameter, increases the spectral resolution of the spectrometer. Simulations also show that transmission efficiency is proportional to the number of zones and the aperture diameter. This thesis presents a theoretical argument for how one zone plate lens can be used to measure all dissolved gases present in HV equipment. Lenses for the visible and infrared ranges were fabricated in the University of Manitoba NSFL Cleanroom. The lenses were then tested in an optical setup. The results show that the visible light experiments were successful in achieving appropriate spectral discrimination by changing the distance between the aperture and the lens. The results from the infrared experiment show that a detector was able to discriminate between full and no incident radiation. / May 2017

Neste texto nós discutimos o fluxo de energia em reações hadrônicas e em fotoprodução. Apresentamos um modelo de produção de partículas com o qual é fácil estudar a deposição de energia na região central e o efeito de partícula dominante. Analisamos dados de produção de partículas carregadas e charrnosas em várias energias. Discutimos o papel individual das interações soft e semi-hard. Fazemos, entre outras, a previsão de que a energia mais altas, uma fração maior da energia das colisões será depositada na região central e, como consequência, a assimetria observada na produção de charme vai diminuir. Estudamos e propomos um teste experimental para a produção de mesons pesados a partir da fragmentação de quarks leves. / We present and apply to several situations a model for particle production. With this model it is possible to understand the energy flow in hadronic reactíons, in photoproduction and also ma.ke predictions for the behaviour of some observables at higher energies. It is also possible to study the individual contributions of soft and semíhard interactions and the individual contributions coming from the central and fragmentation regions. We analyse charged and charmed particle production data at several energies. We predíct, among other things, that an increasing fraction of the reaction energy is going to be released in the central region. As a consequence the asymmetry observed in charm production will decrease. We study and propose as experimental test to heavy meson production from light quark fragmentation.

Neste trabalho, é proposto um esquema de cifragem e decifragem baseado em uma nova técnica de contraste de fase. Esta nova técnica, denominada \"técnica de contraste de fase de ordem zero\", transforma a modulação de fase para intensidade sem a necessidade de uma placa de alteração de fase (dot dielétrico de fase) no plano de Fourier de um correlator óptico 4f. Um processo de codificação, que não utiliza qualquer cálculo iterativo, é aplicado diretamente em uma imagem em níveis de cinza para gerar uma distribuição de fase. Em seguida, um processo de cifragem é realizado através da multiplicação da distribuição de fase por uma distribuição de fase aleatória. A vantagem deste método é o fácil esquema para recuperar a informação em níveis de cinza a partir da máscara de fase decifrada. A máscara de fase cifrada e a chave do sistema foram implementadas em SLMs (Spatial Light Modulators) do tipo LCTV (Liquid Crystal TV). As formas de codificação da imagem em níveis de cinza para gerar as máscaras de fase também foram investigadas. Como resultado, foram implementados dois tipos de EODs (Elementos Ópticos Difrativos) de fase. Um deles funciona no modo de transmissão, o outro, no modo de reflexão. Resultados experimentais mostram a aplicação da técnica de contraste de fase de ordem zero na visualização da informação codificada, tanto em SLM quanto em EODs de fase, e na verificação de padrões cifrados. / In this work, an encryption and decryption scheme based on a new phase contrast technique is proposed. This new technique, called the zero order phase contrast technique, transforma the phase modulation to intensity without the necessity of a phase-changing plate (phase dielectric dot) on the Fourier plane of a 4f optical correlator. A codification process, which does not use any iterative calculation, is applied directly in a gray level image to generate a phase distribution. After this, an encryption process is applied multiplying the phase distribution by a random phase distribution. The advantage of this method is the easy scheme to recover the gray level information from the decryption phase mask. The encrypted phase mask and the key of the system were implemented on Spatial Light Modulators of the kind LCTV. The encoding ways were investigated to generate the phase masks from gray level image, by implementing two kinds of phase Diffractive Optical Elements, operating in transmission and reflection modes. Experimental results show the successfully application of the zero order phase contrast technique in the visualization of encoded information both in Spatial Light Modulators and in phase only Diffractive Optical Elements as well as in the verification of encrypted patterns.

In this PhD Thesis I present some methods for characterizing PA-LCoS microdisplays. It is useful to fully characterize this type of devices for evaluating its performance required in different applications. We have tested its validity in different applications such as diffractive optics elements (DOEs). Finally we apply these microdisplays in a full holographic data storage scheme using a photopolymer as holographic recording medium. We evaluate the capability of PVA/AA photopolymer for this holographic data storage system that incorporates as a novelty a convergent correlator geometry.