Free-space optics (FSO), or wireless optical communications, has received extensive research due to its promise of practically limitless bandwidths. However, FSO has challenges yet to be met for a cost effective realisation. This D.Phil thesis explores a solution using a ferro-electric liquid crystal spatial light modulator (FLC SLM) and binary phase holograms to significantly reduce the hardware complexity of an FSO system with auto-alignment and turbulence compensation. The theory of binary phase hologram is presented and extended to obtain a new algorithm that is suitable for a FLC SLM. The algorithm is able to be used in a demonstration system to broadcast data streams to multiple receivers, showing the capability of using FLC SLM to form any beam configuration. An FSO transmitter is then developed that uses retro-reflectors as markers for the receivers. The transmitter combines an imaging system with the FLC SLM as a reconfigurable beam steering system for acquiring the retro-reflector location. The FLC SLM is also used to reduce aberrations in the optics, resulting in a significant increase in the transmitted beam power density. The accuracy of the acquisition is measured to give a small steering error without the use of a closed loop controller. An optical turbulence simulator, using the principals of binary phase hologram, is constructed to simulate optical beam propagation in turbulent conditions. The simulator accurately produces aberrations that have the same statistics with the theoretical prediction. Analysis of the phase distortion due to turbulence is performed and a wavefront sensorless turbulence compensation method based on the FLC SLM gives significant reduction in calculated bit error rates. New scintillation index derivation for multiple optical beams is described and then used to demonstrate further decrease in bit error rates.

Au cours des vingt dernières années, les facettes céramiques sont devenues une solution esthétique très répandue en raison de leur conception de préparation peu invasive, de leurs propriétés biocompatibles, de leur similitude avec la couleur naturelle des dents, ainsi que de leur translucidité et de leur résistance mécanique aux forces occlusales et à l’usure [1]. La définition des facettes dentaires est celle de « coquilles » très minces, faites sur mesure de matériaux de la couleur de la dent, conçues pour recouvrir la face avant ou la face supérieure des dents afin d' en améliorer l'esthétique et/ou corriger des problèmes occlusaux. Elles sont collées aux dents et pourront en modifier la couleur la forme, et le volume [2].Elles trouvent ainsi de multiples indications à différents endroits sur les arcades dentaires sur les faces vestibulaires des dents antérieures ou plus récemment pour restaurer les surfaces occlusales corriger une occlusion déficiente [3, 4].Ces restaurations modernes se sont développées avec l'arrivée de nouveaux matériaux de reconstructions et de collages, ainsi que de nouveaux modes de conception et fabrication répondant à des exigences de simplicité, de rapidité et de précision.Pour préparer la dent à recevoir une facette, l'oscillation d’inserts ultrasonores a été proposée pour améliorer la finition des lignes marginales et optimiser l’état de surface [5].Pour leur fabrication, outre les méthodes prothétiques classiques, la CFAO (conception assistée par ordinateur - fabrication assistée par ordinateur) au développement exponentiel [6, 7 permet de réaliser une prothèse restauratrice en une seule visite en clinique avec la précision que permettent l’optique (empreintes) et la robotique (fabrication de la facette) ;[8-14]. D’autre part l’apparition de nouvelles céramiques a permis d'améliorer leur esthétique et d'augmenter leur durabilité, qu'elle soit antérieure ou occlusale.Notre première étude portait sur de nouveaux outils permettant d'optimiser la procédure de préparation des facettes. L'utilisation ou non d‘inserts oscillants sur la qualité de l'état de surface de la dent traitées pour une telle préparation. Cette question importante et récurrente, [15] pose le problème de la qualité de l'état de surface destiné à recevoir par collage une pellicule de céramique de faible épaisseur. La pérennité de ce type de prothèse dépend essentiellement du collage avec les tissus dentinaires préparés [16, 17]. La littérature, atteste d’une meilleure qualité de collage entre des surfaces dentaires rugueuses et les matériaux de restauration [18-22]. Toutefois, une question se pose concernant la qualité de cette rugosité lorsque / The first chapter of the thesis relieved the dentists from thinking a lot about the produced roughness regardless to the preparation tool. The roughness is a critical factor to the stability, to the retention, and eventually to the success of the ceramic veneers especially for the esthetic anterior veneers. This will speed up the procedure of achieving a fast treatment for the patients with the CAD-CAM systems. For the upcoming steps, an investigation is recommended to estimate the amount of the inquired roughness to achieve the minimum necessary adhesion value for the retention of the ceramic veneers, and vice versa, another investigation to evaluate the capability of the preparation tools in transferring the same roughness from the preparation tool grains to the target surface (dentin or enamel).152The second study had filled the gap of how to evaluate the IOS systems regardless to the recent common criteria, and the thesis created a novel measure (noise) to be used. The study asks the dentists to pay attention to other criteria to consider when buying an IOS system regardless to the criteria that already exists and had been directed by the producing companies. The thesis states that the noise increases when the direction of the IOS is changed. More attention should be paid at the transitional lines between the scanned surfaces while designing the digital model. An enhancement is demanded to compensate for (or if possible, to eliminate) this noise.

In this dissertation we use the gauge/gravity duality approach to study the dynamics of strongly coupled non-Abelian plasmas. Ultimately, we want to understand the properties of the quark-gluon plasma (QGP), whose scientifc interest by the scientific community escalated exponentially after its discovery in the 2000\'s through the collision of ultrarelativistic heavy ions. One can enrich the dynamics of the QGP by adding an external field, such as the baryon chemical potential (needed to study the QCD phase diagram), or a magnetic field. In this dissertation, we choose to investigate the magnetic effects. Indeed, there are compelling evidences that strong magnetic fields of the order $eB\\sim 10 m_\\pi^2$ are created in the early stages of ultrarelativistic heavy ion collisions. The chosen observable to scan possible effects of the magnetic field on the QGP was the viscosity, due to the famous result $\\eta/s=1/4\\pi$ obtained via holography. In a first approach we use a caricature of the QGP, the $\\mathcal=4$ super Yang-Mills plasma to calculate the deviations of the viscosity as we add a magnetic field. We must emphasize, though, that a magnetized plasma has a priori seven viscosity coefficients (five shears and two bulks). In addition, we also study in this same model the anisotropic heavy quark-antiquark potential in the presence of a magnetic field. In the end, we propose a phenomenological holographic QCD-like model, which is built upon the lattice QCD data, to study the thermodynamics and the viscosity of the QGP with an external strong magnetic field. / Nesta dissertação utilizamos uma abordagem via dualidade gauge/gravity para estudar a dinâmica de plasmas não-Abelianos fortemente interagentes. Nosso objetivo último visa aplicações para o plasma de quarks e glúons (QGP), cujo interesse científico cresceu exponencialmente depois de sua descoberta em meados dos anos 2000 ao colidir-se íons ultrarelativísticos. Podemos enriquecer a dinâmica do QGP ao adicionarmos campos externos, como o potencial químico (para exploração do diagrama de fases hadrônico), ou um campo magnético. Nesta dissertação, tomamos como norte a exploração dos efeitos magnéticos. De fato, acredita-se que campos magnéticos da ordem de $eB\\sim 10 m_\\pi^2$ sejam criados nos estágios iniciais do QGP. O observável escolhido para sondar possíveis efeitos do campo magnético no QGP foi a viscosidade, em partes pelo famoso resultado $\\eta/s=1/4\\pi$ obtido holograficamente. Utilizamos num primeiro momento uma caricatura da QCD, a $\\mathcal=4$ super Yang-Mills para calcular o que muda na viscosidade com o advento do campo magnético. Devemos salientar, contudo, que um plasma altamente magnetizado possui a priori sete coeficientes de viscosidade (cinco de cisalhamento e duas volumétricas). Também exploramos, nesse mesmo modelo, o potencial de um par pesado de quark-antiquark na presença de um campo magnético. Por fim, propomos um modelo holográfico fenomenológico mais semelhante a QCD, sendo ele ``calibrado\'\' pelos dados da QCD na rede, para estudar a termodinâmica e a viscosidade do QGP imerso num forte campo magnético.

<div>Fluid power is widely used in a variety of applications such as construction machines, aerospace, automotive, agricultural machinery, manufacturing, etc. Although this technology has many obvious advantages such as compactness, robustness, high power density, and so forth, there is much room for improvement, of which one of the most important and challenging problems is the noise.</div><div><br></div><div>Different institutes have been researching fluid power noise for decades. However, much of the experimental investigation was based on simple measurement and analysis techniques, which left the designers/researchers no method of understanding the complicated phenomena. A microphone array is a powerful tool that unfortunately has not been introduced to the fluid power noise research. By capturing the magnitude and phase information in space, a microphone array enables the noise source identification, separation, localization and so forth.</div><div><br></div><div>This thesis focuses on implementing the microphone array processing techniques on a synthetic microphone array for fluid power noise diagnostics. Differing from traditional scan-based approaches, the synthetic array is created by synchronizing the non-synchronous measurements to achieve the equivalent effect of a multi-microphone snapshot. The final results will show the power of microphone arrays and provide an economical solution to achieve approximate results when a real microphone array is not available.</div>

A Holografia Digital (HD) é uma ferramenta acessível, rápida e eficiente para análise de efeitos mecânicos em materiais fotoelásticos. Esses materiais apresentam a propriedade da dupla refração, ou birrefringência, quando submetidos a esforços externos e, como consequência, os efeitos dos estados de polarização da luz transmitidos através de sua estrutura podem ser utilizados na análise das distribuições de tensões. As técnicas holográficas tradicionais não possibilitam o armazenamento das fases da onda de luz e, portanto, dificultam a análise quantitativa do campo de tensões e deformações nesses materiais. A Holografia Digital permite contornar essa dificuldade por meio de processos que utilizam diretamente as fases da onda de luz armazenadas. A partir de um interferômetro com duas ondas de referências ortogonalmente polarizadas é possível obter hologramas simultâneos que, ao serem subtraídos durante um processo de reconstrução holográfica digital por método da transformada de Fresnel, fornecem diretamente as diferenças de fases. Dessa forma, a HD mostra ser uma alternativa na análise de problemas em diversas áreas, pois possibilita, através de uma única captura, obter informações sobre as propriedades ópticas e mecânicas dos sistemas de interesse. O objetivo desse trabalho foi, além do desenvolvimento instrumental, criar um método para obtenção das distribuições de tensões que surgem nos materiais fotoelásticos e validá-lo por comparação, tanto com um modelo teórico a partir de fundamentos do método de Elementos Finitos associado à Fotoelasticidade quanto com um método experimental de Fotoelasticidade RGB. Com os procedimentos do método proposto, determinou-se as distribuições de tensões em uma amostra fotoelástica acoplada a uma peça metálica para observar a aplicabilidade do método. Essas etapas levaram a resultados que apontam a possibilidade de se utilizar técnicas e métodos holográficos digitais no estudo das propriedades de materiais fotoelásticos. / The Digital Holographic (DH) is an handy, fast and efficient tool to obtain the stresses distributions in Photoelastic materials. These materials present the double refraction phenomenon also named temporary birefringence when subjected to external forces, therefore, the effects in polarization state of the light transmitted through the structure can be used to analyze the stress distribution. Traditional holographic techniques do not allow the storage phase of the light wave dificulting the analyze these of the distributions. Digital Holographic allows to overcome these difficulties by processes that obtain directly of the storage phase of light. The holographic apparatus applied to generate the holograms registered the interference between two orthogonally polarized reference waves and an object wave transmitted through the samples. The resulting phase maps were reconstructed numerically by the Fresnel transform method. Thereby, the DH is an alternative for the study of problems in several fields, because it allows, through a single capture, to obtain information about the optical and mechanical properties of the systems of interest. The objective of this work was, besides instrumental development, create a method in Digital Holography to obtain the stresses distributions in Photoelastic materials and validate it by comparisions between the theorical Finite Element Method associated with Photoelasticity with the experimental method of Photoelasticity RGB. The procedures of the proposed method were used for determine stresses distributions in a Photoelastic sample with a metal part coupled in your superior base to verified its aplicability. Together, these results demonstrate the possibility of using digital holographic techniques and methods for studying mechanical properties of the Photoelastic materials.

O microscópio é um instrumento de grande relevância para o contexto científico. Dentre as variadas montagens desse instrumento óptico, os microscópios sem lentes têm chamado atenção por serem robustos, reduzidos em tamanho e custo, e ainda possibilitarem imagens com amplo campo de visão (usualmente da ordem de algumas dezenas de mm2). Dentro dessa categoria, existem os microscópios holográficos in-line, os quais obtêm a imagem da amostra a partir da reconstrução numérica de um holograma adquirido por um sensor digital de imagem. Este trabalho tem o objetivo de construir um desses microscópios para observar amostras semitransparentes. O microscópio desenvolvido ao longo deste trabalho tem sua iluminação baseada no uso de um LED associado a um pinhole, cuja finalidade é aumentar a coerência temporal da luz. Com isso, a iluminação proveniente do pinhole percorre uma distância de aproximadamente 10 cm até atingir a amostra, posicionada sobre uma lâmina de vidro. À uma distância mínima da amostra, está posicionado um sensor CMOS, responsável pela aquisição do padrão de interferência da parcela da luz que foi transmitida sem desvio pela amostra e da parte da luz que foi difratada por ela. Esse padrão de intensidade, chamado holograma, é reconstruído numericamente de modo a obter uma boa imagem do objeto-alvo. A reconstrução da imagem medida é feita considerando a propagação da luz de volta ao plano de do objeto e, depois, estimando a fase referente à luz incidente no sensor no instante da medida. Essa primeira etapa resulta na imagem da amostra com a influência de um artefato muito conhecido na holografia: a imagem gêmea. Enquanto a reconstrução de fase reconstrói a imagem de uma forma mais completa, reduzindo a influência de tais artefatos. A reconstrução de fase é feita com o método multialturas, o qual faz uso de mais de uma imagem medida, com distâncias diferentes entre a amostra e o sensor, como entrada para o algoritmo desenvolvido. Utilizando um sensor de 10 MP (3856 x 2764 pixels), com o pixel de 1,67 &mu;m, construímos um microscópio holográfico sem lentes com um campo de visão de quase 30 mm2 e resolução de aproximadamente 3 &mu;m. / The microscope is an instrument of great relevance in the scientific context. Among various assembly of this optic instrument, the lensless microscope have had drawing attention by been robust, with small size and low cost and, in addiction, enable imaging with a large field of view (usually about tens of mm2). Inside this category, there is the in-line holographic microscopes, which achieve the sample image from the numerical reconstruction of a hologram acquired by an image digital sensor. This study have the objective of develop one of these microscopes to image semitransparent samples. The microscope developed over this study has its illumination based on the use of an LED associated with a pinhole, whose purpose is to increase the light temporal coherence. Therefore, illumination from the pinhole goes 10 cm until reach the sample, positioned over the glass slide. From a minimal distance of the sample, a CMOS sensor is positioned, which is responsible to acquire the interference pattern of the transmitted light with the diffracted light. This intensity pattern, called hologram, is numerically reconstructed in order to get a great image of target object. The reconstruction of the measured image is performed considering the back propagation of the light to the object plane and, then, estimating the phase related to the incident light over the sensor at the time of the measurement. This first step results in a sample image influenced by an artifact well-known in the holography: the twin-image. Whereas phase reconstruction reconstruct the image more fully, reducing the artifact influence. Phase reconstruction is performed using the multiheigh method, which uses more than one measured image, with different distances between the sample and sensor, as input to the developed algorithm. Using a 10 MP (3856 x 2764 pixels) sensor, with a pixel size of 1.67 &mu;m, we built a lensless holographic microscope with a field of view near of 30 mm2 and resolution of approximately 3 &mu;m.

Neste trabalho foram realizados a síntese, o crescimento e a caracterização de cristais de Bi 12Ti1-xGaxO20 (BTGaO) para avaliar suas potencialidades tecnológicas em dispositivos do estado sólido, especificamente para registros holográficos. Através da síntese do estado sólido, foi possível determinar um limite máximo de 20% utilizando uma forma estequiométrica de substituição. Considerando a não-estequiometria do sistema Bi2O3:Ga2O3 obtivemos soluções sólidas completas. Os cristais de B12Ti1-xGaxO20 (BTGaO)foram obtidos pelo método de TSSG (Top Seed Solution Growth), utilizando como solvente excesso de Bi2O3 . Cristais de boa qualidade óptica e estrutural foram crescidos utilizando-se taxas de puxamento de 0,2 0,3 mm/h e rotação de 5- 30 rpm . Das medidas de composição dos cristais realizadas por microssonda (EDS) foi possível determinarmos o coeficiente de segregação efetivo do Ga em Bi12TiO20 como sendo maior do que um. Por meio de análise térmica diferencial (DTA) foi possível verificar que a temperatura de fusão diminui de acordo com os diferentes níveis de substituição. Verificamos que a introdução do Ga na matriz de BTO aumenta a atividade óptica (BTO puro de 6.4&#176;/mm; BTGaO-30% de substituição de 9.8&#176;/mm) e para o BGaO nominalmente puro encontramos um valor da ordem de 150% maior (15.9&#176;/mm). A corrente no escuro aumentou em quatro ordens de grandeza (ID=10-9 A) em relação àquela presente nos cristais de BTO nominalmente puro (ID=10-13 A) enquanto nenhuma fotocorrente foi detectada. O coeficiente de absorção óptica diminuiu em todo espectro visível e o coeficiente eletroóptico não apresentou variação significativa (5,20pm/V para o BTO e 5,4 - 5,6pm/V para os cristais de BTGaO). A análise das propriedades ópticas indicam que os cristais de Bi12Ti1-xGaxO20 são inadequados para registros holográfico no vermelho. Porém sua maior transparência na região do espectro visível pode qualificá-lo como um novo meio para dispositivos optoeletrônicos / In this work the synthesis, the growth and crystal characterization of Bi 12Ti1-xGaxO20 (BTGaO) have been carried out to evaluate its technological potentialities in solid state devices, specifically for holographic recorders. Through the synthesis of the solid state, it was possible to determine a maximum limit of 20% using an stoichioinetric form of substitution. Considering the non-stoichiometry of the Bi2O3:Ga203 system we got full solid solutions. The crystals of BTGaO have been gotten by the TSSG method (Top Seed Solution Growth), using as solvent excess of BiO3. Crystals with good optic and structural quality have been grown using pulling rates of 0.2-0.3 mm/h and rotation of 5-30rpm. From the measures of composition through microprobe(EDS) in crystals, it was possible to determine the effective coefficient of segregation of Ga in Bi12TiO20 as being bigger than one. By means of differential thermal analysis (DTA), it was possible to verify that the melting temperature diminishes in accordance with the different leveis of substitution. We verify the introduction of Ga in the host of BTO increases the optical activity (in pure BTO = 6.4&#176;/mm; 9.8&#176;/mm 30% of substitution) and for nominally pure BGaO vve find a value 150% higher (15.9&#176;/mm). The dark current increase in four orders of magnitude (ID=10-9 A) in relation to crystals of pure BTO (ID=10-13 A) while not any photocurrent was detected. The optical absorption coefficient diminishes in ali visible spectrum. The electrooptical coefficient did not present significant variation (5.20pm/V for BTO and 5.4-5.6pm/V for crystals of BTGaO). The analysis of the optical properties indicates that the crystals of Bi12Ti1-xGaxO20 are inadequate for holographic recorders. However its bigger transparency in the region of the visible specter can chancterize it as new medium for optoeletronical devices

A interferometria holográfica é um poderoso método óptico para observação de fenômenos perturbativos e na análise de superfícies, sendo extremamente útil em aplicações em pesquisa básica, biomédicas e tecnológicas. Os cristais fotorefrativos se apresentam como um meio atrativo para registro de hologramas. O fenômeno que caracteriza esses cristais é o efeito fotorrefrativo. Tal efeito consiste na modulação do índice de refração através de fotoindução e efeito eletro-óptico linear (Efeito Pockels), o que permite o registro de hologramas de fase em volume. Entre as características que recomendam os cristais fotorrefrativos para interferometria holográfica podemos citar: o processo de registro e leitura ocorre de maneira dinâmica através da técnica de mistura de duas ondas; o fato de serem meios revers´?veis dispensando processamento químico e a boa resolução implicando imagens holográficas de boa qualidade. Analisamos as diversas tensões que ocorrem no processo mastigatório, estudando principalmente a concentração de cargas e as dissipações nesse processo, utilizando a técnica holográfica de dupla exposição e o cristal fotorrefrativo Bi12SiO20 (BSO), da família das Silenitas, como meio de registro. O estudo em crânio seco e a simulação dos principais feixes dos músculos da mastigação permitem realizar a contração dos mesmos, com aproximação melhor que os métodos de elementos finitos e resinas fotoelásticas, em estruturas anisotrópicas como o crânio. / The holographic interferometry is a powerful optical method for observation of the disturbance phenomena and in the analysis of surface, being extremely useful in application in basic research, biomedical and technological. The photorefractive crystals present as an attractive holographic recording medium. The phenomenon that characterize these crystals is the photorefractive effect. Such effect consistis of the index of refraction modulation grating via the linear eletro-optic effect (the Pockels effect) and photoindution, that it allow phase holographic recording in volume. Among the characteristics that admit the photorefractive crystals for holographic interferometry we can cite: recording and reading tecniques to occur in dynamics way through the tecnique of two-wave mixing, it is reversible medium resulting holographic images of good quality. We analyze the varied strains that occur in the masticatory process, mainly studying the load concentration and the dissipation in this process, using the double-exposure holographic technique and the photorefractive crystals Bi12SiO20 (BSO), of the sillenite family, as holographic recording medium. The study in dry skull and the simulation of main beams of the mastication muscles allow to realize the concentration of the same ones, with better approach than the methods of finite elements and photoelastics resins, in anisotropic structures as the skull.

"Hearing loss affects approximately 1 in 10 people in the world and this percentage is increasing every year. Some of the most common causes of hearing loss are disorders of the middle-ear. Early detection and diagnosis of hearing loss as well as research to understand the hearing processes depend on medical and research tools for quantification of hearing capabilities and the function of the middle-ear in the complex acousto-mechanical transformation of environmental sounds into vibrations of the middle-ear, particular of the human tympanic membrane (TM or eardrum). Current ear exams assess the state of a patient’s hearing capabilities mainly based on qualitative evaluation of the healthiness of the TM. Existing quantitative clinical methods for description of the motion of the TM are limited to either average acoustic estimates (admittance or reflectance) or single-point displacement measurements. Such methods could leave examiners and researchers blind to the complex spatio-temporal response of the nanometer scale displacements of the entire TM. Current state-of-the-art medical research tools provide full-field nanometer displacement measurements of the surface of the human TM excited by steady state (tonal) stimuli. However, to fully understand the mechanics of hearing, and the complex acousto-mechanical characteristics of TM in particular, new tools are needed for full-field high-speed characterization of the nanometer scale displacements of the human TM subjected to impulse (wideband) acoustic excitation. This Dissertation reports the development of a new high-speed holographic system (HHS) for full-field nanometer transient (i.e., > 10 kHz) displacement measurement of the human middle-ear and the tympanic membrane, in particular. The HHS allows spatial (i.e., >500k data points) and temporal (i.e., > 40 kHz) resolutions that enable the study of the acoustical and mechanical characteristics of the middle-ear at a level of detail that have never been reached before. The realization of the HHS includes the development and implementation of novel phase sampling and acquisition approaches that allow the use of state-of-the-art high-resolution (i.e., >5 MP) and high-speed (> 80,000 fps) cameras through modular and expandable control architectures. The development of novel acquisition approaches allows the use of conventional speed (i.e., <20 fps) cameras to realize high-temporal resolutions (i.e., <15 us) at equivalent sampling rates of > 50,000 fps with minimum hardware cost and modifications. The design and implementation of novel spatio-temporal phase sampling methods utilize the high temporal resolution (i.e., < 5 us exposure) and frame rate (i.e., >80,000 fps) of high-speed cameras without imposing constraints on their spatial resolution (i.e., >20 um pixel size). Additionally, the research and in-vivo applications capabilities of the HHS are extended through the development and implementation of a holographic otoscope head (OH) and a mechatronic otoscope positioner (MOP). The large (i.e., > 1 GB with > 8x10^9 parameters) spatio-temporal data sets of the HHS measurements are automatically processed by custom parallel data mining and interpretation (PDMI) methods, which allow automatic quantification of medically relevant motion parameters (MRMPs), such as modal frequencies, time constants, and acoustic delays. Such capabilities could allow inferring local material properties across the surface of the TM. The HHS is a new medical tool that enables otologists to improve the quality of diagnosis and treatments as well as provides researchers with spatio-temporal information of the hearing process at a level of detail never reached before. "

Recent advances in microelectronics and packaging industry are characterized by a progressive miniaturization in response to a general trend toward higher integration and package density. Corresponding to this are the challenges to traditional manufacturing processes. Some of these challenges can be satisfied by laser micromachining, because of its inherent advantages. In laser micromachining, there is no tool wear, the heat affected zone can be localized into a very small area, and the laser micromachining systems can be operated at a very wide range of speeds. Some applications of laser micromachining include pulsed Nd:YAG laser spot welding for the photonic devices and laser microdrilling in the computer printed circuit board market. Although laser micromachining has become widely used in microelectronics and packaging industry, it still produces results having a variability in properties and quality due to very complex phenomena involved in the process, including, but not limited to, heat transfer, fluid flow, plasma effects, and metallurgical problems. Therefore, in order to utilize the advantages of laser micromachining and to achieve anticipated results, it is necessary to develop a thorough understanding of the involved physical processes, especially those relating to microelectronics and packaging applications. The objective of this Dissertation was to study laser micromachining processes, especially laser drilling and welding of metals or their alloys, for the microscale applications. The investigations performed in this Dissertation were based on analytical, computational, and experimental solutions (ACES) methodology. More specifically, the studies were focused on development of a consistent set of equations representing interaction of the laser beam with materials of interest in this Dissertation, solution of these equations by finite difference method (FDM) and finite element method (FEM), experimental demonstration of laser micromachining, and correlation of the results. The contributions of this Dissertation include: 1)development of a finite difference method (FDM) program with color graphic interface, which has the capability of adjusting the laser power distributions, coefficient of energy absorption, and nonlinear material properties of the workpiece as functions of temperature, and can be extended to calculate the fluid dynamic phenomena and the profiles of laser micromachined workpieces, 2)detailed investigations of the effect of laser operating parameters on the results of the profiles and dimensions of the laser microdrilled or microwelded workpiece, which provide the guideline and advance currently existing laser micromachining processes, 3)use, for the first time, of a novel optoelectronic holography (OEH) system, which provides non-contact full-field deformation measurements with sub-micrometer accuracy, for quantitative characterization of thermal deformations of the laser micromachined parts, 4)experimental evaluations of strength of laser microwelds as the function of laser power levels and number of microwelds, which showed the lower values than the strength of the base material due to the increase of hardness at the heat affected zone (HAZ) of the microwelds, 5)measurements of temperature profiles during laser microwelding, which showed good correlations with computational results, 6)detailed considerations of absorption of laser beam energy, effect of thermal and aerodynamic conditions due to shielding gas, and the formation of plasma and its effect on laser micromachining processes. The investigations presented in this Dissertation show viability of the laser micromachining processes, account for the considerations required for a better understanding of laser micromachining processes, and provide guideline which can help explaining and advancing the currently existing laser micromachining processes. Results of this Dissertation will facilitate improvements and optimizations of the state-of-the-art laser micromachining techniques and enable the emerging technologies related to the multi-disciplinary field of microelectronics and packaging for the future.