Pulsos ultracurtos de laser vêm sendo usados tanto para estudar e desenvolver processos ópticos não lineares em materiais, quanto para o seu processamento visando as mais diversas aplicações tecnológicas. Neste trabalho, estas duas áreas (estudos de não linearidades e processamento de materiais) foram exploradas em distintas amostras vítreas. Primeiramente, investigamos o espectro das propriedades ópticas não lineares de terceira ordem de vidros oxifluoroboratos de chumbo (50BO 1,5 - (50-x)PbF2 - xPbO) em função da variação da composição. Os espectros não lineares foram determinados na região do visível e infravermelho próximo pela técnica de varredura-z, utilizando um sistema laser de Ti: safira (775 nm, 150 fs, 1 kHZ) juntamente com um amplificador óptico paramétrico (470 a 2000 nm). Os resultados revelaram que a formação de oxigênios não ligantes favorece a resposta óptica não linear do material; o vidro com x = 50 apresentou as maiores não linearidades de terceira ordem, com índice de refração não linear de aproximadamente 4,7 x \'10 POT.-19\' \'M POT.2\'/W para comprimentos de onda entre 470 a 1550 nm, e coeficiente de absorção de dois fótons da ordem de 1 cm/GW, na região de engrandecimento de ressonância. Estes resultados, associados com a análise do fator de mérito e medidas de limitação óptica, sugerem que esses vidros têm potencialidades para aplicações em limitadores de potência e chaves puramente ópticas. Com relação ao processamento de materiais, utilizamos a técnica de microestruturação com laser de femtossegundos para produzir microestruturas em vidros borato de chumbo e borosilicatos. Foi possível obter linhas na superfície destes materiais, cuja largura pode ser controlada no intervalo de 3 a 35 µm pela alteração das condições de focalização, energia e velocidade de varredura do feixe. Ainda, através da irradiação com pulsos de femtossegundos foi possível produzir nanopartículas de cobre, cujo tamanho está em torno de 15 nm, tanto no volume quanto na superfície de um vidro borosilicato. Observamos que existe uma combinação ótima entre a velocidade de varredura do laser e a temperatura de tratamento térmico que permite a formação dessas nanopartículas apenas nas regiões irradiadas. / Ultrashort laser pulses have been used to study and develop nonlinear optical processes in materials, as well as for their processing, aiming at several technological applications. In this work, both areas (study of optical nonlinearities and materials processing) were exploited for different glass materials. Initially, we have studied the third order nonlinear optical spectrum of lead oxifluoroborate glasses (50BO 1,5 - (50-x)PbF2 - xPbO) as a function of the composition. The optical nonlinearities were determined from the visible to the near infrared employing the Z-scan technique, using a Ti: sapphire laser system (775 nm, 150 fs, 1 kHZ) and an optical parametric amplifier (470 a 2000 nm) as excitation sources. The results revealed that the formation of non-bridging oxygens favors the nonlinear optical properties of the material; the glass with x = 50 presents the higher third order nonlinearities, exhibiting a nonlinear index of refraction of about 4,7 x \'10 POT.-19\' \'M POT.2\'/W at the range of 470 - 1550 nm, and a two-photon absorption coefficient of approximately 1 cm/GW at the resonant enhancement region. Figure of merit analysis and optical limiting measurements suggest that these glasses have potential for applications in optical limiting and all-optical switching. Regarding materials processing, we have used femtosecond laser micromachining to produce microstructures in lead borate and borosilicate glasses. We were able to produce lines with controlled widths, from 3 - 35 µm, on the surface of the glasses by changing the focus, speed and energy of the laser beam. Moreover, using femtosecond laser pulses we obtained copper nanoparticles on the surface as well as in the bulk of a borosilicate glass. We have observed that there is an optimal combination between scanning speed and annealing temperature to promote the formation of nanoparticles at the regions irradiated by the laser.

This thesis deals with optical design of f-theta lens for purposes of precision micromachining using a laser beam. Optical design consists of creating a nominal design according to specifications given by Meopta – optika s.r.o company and a tolerance analysis, which describes manufacturability of given design. Specifications given are most importantly diffraction limited image quality, correction of distortion throughout the field and telecentricity of systém in image space. F-theta lens in this thesis was created using an optical design software called Zemax.

This thesis introduces two ortho-planar MEMS devices that can be used to position microcomponents: the XZ Micropositioning Mechanism and the XYZ Micromanipulator. The displacement and force relationships are presented. The devices were fabricated using surface micromachining processes and the resulting mechanisms were tested. A compliant XYZ Micromanipulator was also designed to reduce backlash and binding. In addition, several other MEMS positioners were fabricated and tested: the Micropositioning Platform Mechanism (MPM), the Ortho-planar Twisting Micromechanism (OTM), and the Ortho-planar Spring Micromechanism (OSM).

This dissertation presents the fabrication of hollow optical waveguides integrated on planar substrates. Similar in principle to Bragg waveguides and other photonic crystal waveguides, the antiresonant reflecting optical waveguide (ARROW) is used to guide light in hollow cores filled with liquids or gases. Waveguides with liquid or gas cores are an important new building block for integrated optical sensors. The fabrication method developed for hollow ARROW waveguides makes use of standard microfabrication processes and materials. Dielectric layers are deposited on a silicon wafer using plasma-enhanced chemical vapor deposition (PECVD) to form the bottom layers of the ARROW waveguide. A sacrificial core material is then deposited and patterned. Core materials used include aluminum, SU-8 and reflowed photoresist, each resulting in a different core geometry. Additional dielectric layers are then deposited, forming the top and sides of the waveguide. The sacrificial core is then removed in an acid solution, resulting in a hollow ARROW waveguide. Experiments investigating the mechanical strength of the hollow waveguides and the etching characteristics of the sacrificial core suggest design rules for the different core types. Integration of solid-core waveguides is accomplished by etching a ridge into the top dielectric layer of the ARROW structure. Improved optical performance can be obtained by forming the waveguides on top of a raised pedestal on the silicon substrate. Loss measurements on hollow ARROW waveguides fabricated in this manner gave loss coefficients of 0.26 cm-1 for liquid-core waveguides and 2.6 cm-1 for air-core waveguides. Fluorescence measurements in liquid-core ARROW waveguides have achieved single-molecule detection sensitivity. Integrated optical filters based on ARROW waveguides were fabricated, and preliminary results of a capillary electrophoresis separation device using a hollow ARROW indicate the feasibility of such devices for future investigation.

The development of millimeter-wave (30-300 GHz) sensors and communications systems has a long history of interest, spanning back almost six decades. In particular, mm-wave radars have applications as automotive radars, in remote atmospheric sensing applications, as landing radars for air and spacecraft, and for high precision imaging applications. Mm-wave radar systems have high angular accuracy and range resolution, and, while susceptible to atmospheric attenuation, are less susceptible to optically opaque conditions, such as smoke or dust. This dissertation document will present the initial steps towards a new approach to the creation of a mm-wave radar system at 94 GHz. Specifically, this dissertation presents the design, fabrication and testing of various components of a highly integrated mm-wave a 94 Ghz monopulse radar transmitter/receiver. Several architectural approaches are considered, including passive and active implementations of RF monopulse comparator networks. These architectures are enabled by a high-performance three-dimensional rectangular coaxial microwave transmission line technology known as PolyStrataTM as well as silicon-based IC technologies. A number of specific components are examined in detail, including: a 2x2 PolyStrata antenna array, a passive monopulse comparator network, a 94 GHz SiGe two-port active comparator MMIC, a 24 GHz RF-CMOS 4-port active monopulse comparator IC, and a series of V- and W-band corporate combining structures for use in transmitter power combining applications. The 94 GHz cavity-backed antennas based on a rectangular coaxial feeding network have been designed, fabricated, and tested. 13 dB gain for a 2 x 2 array, as well as antenna patterns are reported. In an effort to facilitate high-accuracy measurement of the antenna array, an E-probe transition to waveguide and PolyStrata diode detectors were also designed and fabricated. AW-band rectangular coaxial passive monopulse comparator with integrated antenna array and diode detectors have also been presented. Measured monopulse nulls of 31.4 dB in the ΔAZ plane have been demonstrated. 94-GHz SiGe active monopulse comparator IC and 24 GHz RF-CMOS active monopulse comparator RFIC designs are presented, including detailed simulations of monopulse nulls and performance over frequency. Simulations of the W-band SiGe active monopulse comparator IC indicate potential for wideband operation, with 30 dB monopulse nulls from 75-105 GHz. For the 24-GHz active monopulse comparator IC, simulated monopulse nulls of 71 dB and 68 dB were reported for the azimuthal and elevational sweeps. Measurements of these ICs were unsuccessful due to layout errors and incomplete accounting for parasitics. Simulated results from a series of rectangular coaxial power corporate power combining structures have been presented, and their relative merits discussed. These designs include 2-1 and 4-1 reactive, Wilkinson, and Gysel combiners at V- and W-band. Measured back-to-back results from Gysel combiners at 60 GHz included insertion loss of 0.13 dB per division for a 2-1 combination, and an insertion loss of 0.3 dB and 0.14 dB for "planar" and "direct" 4-1 combinations, respectively. At 94 GHz, a measured insertion loss of 0.1 dB per division has been presented for a 2-1 Gysel combination, using a back-to-back structure. Preliminary designs for a solid-state power amplifier (SSPA) structure have also been presented. Finally, two conceptual monopulse transceivers will be presented, as a vehicle for integrating the various components demonstrated in this dissertation. / Ph. D.

De nombreux processus fondamentaux ont lieu sur des échelles de temps femtosecondes à plusieurs centaines de picosecondes. En outre, les demandes continues d'augmentation de résolution et de précision dans l'industrie du micro-usinage de pointe exigent la compréhension fine des mécanismes physiques d'ablation et l'identification précise des conditions optimales de mise en œuvre des systèmes laser femtosecondes. Ces systèmes doivent ainsi permettre la production de structures de taille micrométrique de manière contrôlée et étalonnée. Dans ce travail de thèse, nous étudions l'interaction d'un laser femtoseconde (500 fs @ 1025 nm) avec une cible diélectrique en utilisant un banc d'essai spécifique. La première partie de cet ouvrage décrit les aspects fondamentaux du dépôt d'énergie laser dans les diélectriques (SiO2) et de dissipation au sein du réseau ainsi que le processus d'ablation de la matière, au moyen de techniques pompe-pompe et pompe-sonde résolues en temps. L'étude expérimentale est accompagnée d'une modélisation prenant en compte la propagation du faisceau dans la matière (équation de Helmholtz monodimensionnelle), le processus de dépôt d'énergie en régime hors équilibre (modèle à deux températures) et l'ionisation du matériau (équation de population de la densité d'électrons libres). Enfin, nous mettons en évidence l'intérêt des lasers femtosecondes pour la modification de la matière (notamment pour l'endommagement en surface et l'ablation) et les applications, notamment dans le domaine du micro-usinage et de la chirurgie de la cornée par laser. / Numerous fundamental processes take place on time scales from several femtoseconds to hundreds of picoseconds. Moreover, the continuous demands of downscaling and increase of precision in the cutting-edge micromachining industry require the comprehension of the physical mechanisms and the identification of key laser parameters for an optimized use of femtosecond laser systems. Those systems shall allow production of controlled and calibrated micrometer-size structures with high spatial selectivity. In this PhD work, we study the interaction of a femtosecond laser (500 fs @ 1025 nm) with a dielectric target using a dedicated test-bench. The first part of this work describes the fundamental aspects of laser energy deposition in dielectrics (SiO2), its redistribution to the lattice and the process of laser ablation by means of pump-pump and time-resolved pump-probe experiments. The experimental study is accompanied by a computational modeling taking into account the beam propagation (one-dimensional Helmholtz equation), the non-equilibrium process of the energy deposition (two-temperature model) and the matter ionisation (rate equation describing the free electron density change). Finally, we put in evidence the interest of femtosecond lasers for material modification (notably for surface damage and ablation) which high specific benefit in such applications as micromachining and laser corneal surgery.

Nos últimos anos, o estudo do microfresamento tem recebido grande atenção devido a seu uso na fabricação de microcomponentes como células de combustível, microatuadores ou sensores, circuitos integrados, etc. O objetivo deste trabalho é apresentar os fundamentos do fresamento aplicados ao microfresamento. Para isto foi investigado, em escala reduzida, o comportamento de alguns princípios fundamentais da usinagem convencional, tais como espessura de corte instantânea, espessura de corte média, força de corte, pressão específica de corte, potência de corte, entre outros. A importância deste trabalho justifica-se pela necessidade de se entender como estes princípios comportam-se em escalas reduzidas. Inicialmente foi realizada uma investigação da literatura a fim de mostrar a origem de alguns destes princípios fundamentais. Em seguida, uma análise critica destes fundamentos foi apresentada e experimentos foram realizados com o intuito de confrontar o levantamento teórico com os resultados práticos. Para isso foram realizados testes de microfresamento com duas microfresas de metal duro constituídas de dois dentes cada uma com diâmetro de 0,8 mm. O raio da aresta de corte de cada ferramenta foi medido usando um microscópio confocal e os valores variaram de 1,8 \'mü\'m a 3,3 \'mü\'m. O material usado nos experimentos foi um alumínio liga (RSA 6061) de grãos ultrafinos (valor médio de 1 \'mü\'m). O fresamento adotado foi o frontal parcial (não engajado) com penetrações de trabalho de 0,2 mm e 0,4 mm. Os avanços por dente usados foram de 5 \'mü\'m e 10 \'mü\'m a uma profundidade de usinagem de 50 \'mü\'m. A máquina usada foi um centro de usinagem CNC de três eixos com potência nominal de 18 kw e rotação máxima de 24000 RPM. A máxima velocidade de corte alcançada foi de 50 m/min. Para coletar o sinal das forças de usinagem um dinamômetro piezoelétrico modelo 9256 C2 (Kistler) foi usado. Os resultados experimentais mostraram que o comportamento da variação da força de corte, o aumento da pressão específica de corte com o decréscimo da espessura de corte, energia de corte, potência de corte e representação da energia e potência de corte com base na força de corte média durante a formação do cavaco, são semelhantes ao comportamento destes parâmetros durante a usinagem convencional. Com base nestes resultados, foi mostrado que os fundamentos do fresamento podem ser aplicados em microfresamento para explicar o comportamento da microusinagem. / Recently, micro end milling is a subject that has received a large contribution due to its feasibility to be applied to the manufacturing of micro components such as fuel cells, micro actuators and sensors, integrated circuits, etc. The objective of this study is to present fundamental principles of machining of end milling operation applied to the micro end milling operation. It will be investigated the behavior at small scale of some known conventional machining parameters such as instantaneous thickness of cut, average thickness of cut, cutting force, specific cutting pressure, cutting power among others. The relevance of this study is justified by the need of understanding how those cutting parameters behave when the machining scale is reduced. Firstly, a review of the literature was carried out in order to show the origin of some fundamental principles of machining of materials. Thereafter, a critical analysis was held on these fundamentals and experimental cutting tests were designed and carried out aiming to comparing the experimental results with the expected trend shown by those parameters in conventional machining scale. The micro end milling tests used two carbide two teeth micro end mills with a diameter of 0,8 mm. The cutting edge of each tool was measured using a confocal optical profiler and the values ranged from 1,8 \'mü\'m up to 3,3 \'mü\'m. The workpiece material used in the cutting experiments was an ultra fine grain (average 1 \'mü\'m) aluminum alloy (RSA 6061). The machining operation was partial (not engaged) end milling with radial depths of cut of 0,2 mm and 0,4 mm. The feed per tooth used were 5 \'mü\'m and 10 \'mü\'m at constant depth of cut of 50 \'mü\'m. The machine tool used was a three axis CNC machining center with 18 kw nominal power and maximum spindle speed of 24000 RPM. At the maximum spindle speed the maximum cutting speed reached was 50 m/min. A mini piezoelectric dynamometer multicomponent model 9256 C2 (Kistler) was used to gather the cutting forces signals during machining. Therefore, the experimental results showed that the cutting force variation behavior, the increase of specific cutting pressure with the decrease of thickness of cut, cutting energy, cutting power, representing the energy and cutting power representation based on the average cutting force during chip formation are similar to the behavior of these parameters during conventional machining. Based upon that it is shown that the fundamental principles may well be applied to explain the machining behavior at very reduced scales during micro end milling operation.

Nos últimos anos, o estudo do microfresamento tem recebido grande atenção devido a seu uso na fabricação de microcomponentes como células de combustível, microatuadores ou sensores, circuitos integrados, etc. O objetivo deste trabalho é apresentar os fundamentos do fresamento aplicados ao microfresamento. Para isto foi investigado, em escala reduzida, o comportamento de alguns princípios fundamentais da usinagem convencional, tais como espessura de corte instantânea, espessura de corte média, força de corte, pressão específica de corte, potência de corte, entre outros. A importância deste trabalho justifica-se pela necessidade de se entender como estes princípios comportam-se em escalas reduzidas. Inicialmente foi realizada uma investigação da literatura a fim de mostrar a origem de alguns destes princípios fundamentais. Em seguida, uma análise critica destes fundamentos foi apresentada e experimentos foram realizados com o intuito de confrontar o levantamento teórico com os resultados práticos. Para isso foram realizados testes de microfresamento com duas microfresas de metal duro constituídas de dois dentes cada uma com diâmetro de 0,8 mm. O raio da aresta de corte de cada ferramenta foi medido usando um microscópio confocal e os valores variaram de 1,8 \'mü\'m a 3,3 \'mü\'m. O material usado nos experimentos foi um alumínio liga (RSA 6061) de grãos ultrafinos (valor médio de 1 \'mü\'m). O fresamento adotado foi o frontal parcial (não engajado) com penetrações de trabalho de 0,2 mm e 0,4 mm. Os avanços por dente usados foram de 5 \'mü\'m e 10 \'mü\'m a uma profundidade de usinagem de 50 \'mü\'m. A máquina usada foi um centro de usinagem CNC de três eixos com potência nominal de 18 kw e rotação máxima de 24000 RPM. A máxima velocidade de corte alcançada foi de 50 m/min. Para coletar o sinal das forças de usinagem um dinamômetro piezoelétrico modelo 9256 C2 (Kistler) foi usado. Os resultados experimentais mostraram que o comportamento da variação da força de corte, o aumento da pressão específica de corte com o decréscimo da espessura de corte, energia de corte, potência de corte e representação da energia e potência de corte com base na força de corte média durante a formação do cavaco, são semelhantes ao comportamento destes parâmetros durante a usinagem convencional. Com base nestes resultados, foi mostrado que os fundamentos do fresamento podem ser aplicados em microfresamento para explicar o comportamento da microusinagem. / Recently, micro end milling is a subject that has received a large contribution due to its feasibility to be applied to the manufacturing of micro components such as fuel cells, micro actuators and sensors, integrated circuits, etc. The objective of this study is to present fundamental principles of machining of end milling operation applied to the micro end milling operation. It will be investigated the behavior at small scale of some known conventional machining parameters such as instantaneous thickness of cut, average thickness of cut, cutting force, specific cutting pressure, cutting power among others. The relevance of this study is justified by the need of understanding how those cutting parameters behave when the machining scale is reduced. Firstly, a review of the literature was carried out in order to show the origin of some fundamental principles of machining of materials. Thereafter, a critical analysis was held on these fundamentals and experimental cutting tests were designed and carried out aiming to comparing the experimental results with the expected trend shown by those parameters in conventional machining scale. The micro end milling tests used two carbide two teeth micro end mills with a diameter of 0,8 mm. The cutting edge of each tool was measured using a confocal optical profiler and the values ranged from 1,8 \'mü\'m up to 3,3 \'mü\'m. The workpiece material used in the cutting experiments was an ultra fine grain (average 1 \'mü\'m) aluminum alloy (RSA 6061). The machining operation was partial (not engaged) end milling with radial depths of cut of 0,2 mm and 0,4 mm. The feed per tooth used were 5 \'mü\'m and 10 \'mü\'m at constant depth of cut of 50 \'mü\'m. The machine tool used was a three axis CNC machining center with 18 kw nominal power and maximum spindle speed of 24000 RPM. At the maximum spindle speed the maximum cutting speed reached was 50 m/min. A mini piezoelectric dynamometer multicomponent model 9256 C2 (Kistler) was used to gather the cutting forces signals during machining. Therefore, the experimental results showed that the cutting force variation behavior, the increase of specific cutting pressure with the decrease of thickness of cut, cutting energy, cutting power, representing the energy and cutting power representation based on the average cutting force during chip formation are similar to the behavior of these parameters during conventional machining. Based upon that it is shown that the fundamental principles may well be applied to explain the machining behavior at very reduced scales during micro end milling operation.

Femtosecond laser has been an essential tool for nonlinear optics and materials processing at micrometer scale, in which chalcogenide and heavy metal oxide glasses have received special attention not only for their high third-order optical nonlinearities but also due to their transparency up to the infrared regions. Although metallic nanoparticles are expected to improve the optical properties of glasses, there are no enough experimental researches about their influence on the nonlinear refractive index (n2) and nonlinear absorption coefficient (&#946), moreover at femtosecond regime. Based on the scientific and technological interests on highly nonlinear glasses, the goal of this thesis was to apply femtosecond laser pulses in two main domains: (i) at the basis of fundamental science, to study the effect of metallic nanoparticles in the third-order nonlinear optical properties of glasses; and (ii) at the field of applied science, aiming the development of photonic devices, performed by the fabrication of 3D optical waveguides containing metallic nanoparticles. This aim was achieved through the techniques of z-scan and femtosecond laser micromachining, which provided the nonlinear optical characterization and waveguides development, respectively. First, we analyzed the third-order nonlinear optical properties of the GeO2-Bi2O3 glass containing gold nanoparticles, which promoted saturation of the absorption in the region of the surface plasmon resonance band. On the other hand, these gold nanoparticles did not affect the n2 that kept constant in the wavelength range of 480 - 1500 nm. The same features were investigated for a Pb2P2O7-WO3 matrix doped with copper nanoparticles. In contrast to the gold doped ones, these samples showed a slight enhancement of the nonlinear refractive index when the energy of the excitation approaches the surface plasmon band. We also found out that the Pb2P2O7-WO3 matrix is a good host to grow silver nanoparticles by fs-laser micromachining. Similarly, copper nanoparticles were produced in a borosilicate glass using single-step laser processing. The explanation for metallic nanoparticle formation is addressed in this thesis, as well as, its application in waveguides. Thus, we demonstrated the functionality of optical waveguides containing Cu0 or Ag0 nanoparticles. Still based on the technological interests on glasses doped with nanoparticles, we showed a single-step synthesis of silver sulfide nanoparticles in chalcogenide glass, which was carried in partnership with researches at Princeton University. The materials investigated in this PhD work are of great importance for photonics, in which the synthesis of nanoparticles, fabrication of waveguides and nonlinear optical characterization have been performed. / O laser de femtossegundos tem sido uma ferramenta essencial tanto para a óptica não-linear quanto para o processamento de materiais na escala micrométrica, na qual os vidros calcogenetos e óxidos de metais pesados têm recebido atenção especial, não apenas pelas suas elevadas não-linearidades ópticas de terceira ordem, mas também devido à sua transparência até o infravermelho. Embora seja esperado que nanopartículas metálicas melhorem as propriedades ópticas dos vidros, não existe investigações experimentais suficientes sobre a sua influência no índice de refração não linear (n2) e no coeficiente de absorção linear (&#946), sobretudo no regime de femtossegundos. Com base nos interesses científicos e tecnológicos de vidros altamente não-lineares, o objetivo deste trabalho foi aplicar pulsos laser de femtossegundos em dois domínios principais: (i) na campo da ciência fundamental, para estudar o efeito de nanopartículas metálicas nas propriedades ópticas não lineares de terceira ordem destes materiais; e (ii) no domínio da ciência aplicada, visando o desenvolvimento de dispositivos fotônicos, realizado pelo fabricação de guias de onda tridimensionais contendo nanopartículas metálicas. Este objetivo foi alcançado através das técnicas de varredura-z e microfabricação com laser de femtossegundos, que proporcionaram a caracterização óptica não-linear e o desenvolvimento de guias de onda, respectivamente. Primeiramente, foram investigadas as propriedades ópticas não-lineares de terceira ordem do vidro GeO2-Bi2O3 contendo nanopartículas de ouro, as quais promoveram saturação da absorção na região da banda de ressonância de plásmon. Por outro lado, essas nanopartículas não afetaram o n2, que se manteve constante no intervalo de comprimento de onda 480 - 1500 nm. As mesmas características foram investigadas para uma matriz Pb2P2O7-WO3 dopada com nanopartículas de cobre. Em contraste com os vidros dopados com ouro, estas amostras apresentaram um ligeiro aumento do índice de refração não linear quando a energia de excitação está próxima da banda de ressonância de plásmon. Observou-se ainda que a matriz Pb2P2O7-WO3 é ideal para a obtenção de nanopartículas de prata através da microfabricação com laser de femtossegundos. Similarmente, nanopartículas de cobre foram produzidas em vidro de borosilicato usando somente uma varredura a laser. A explicação para a formação de nanopartículas metálicas é abordada nesta tese, bem como sua aplicação em guias de onda. Deste modo, demonstrou-se a funcionalidade de guias de onda ópticos compostos por nanopartículas de Cu0 e Ag0. Ainda com base nos interesses tecnológicos em vidros dopados com nanopartículas, demonstrou-se uma síntese de nanopartículas de sulfeto de prata em vidro calcogeneto usando o processamento de única etapa, realizada em parceria com pesquisadores da Universidade de Princeton. Os materiais investigados neste trabalho de doutorado são de grande importância para aplicações em fotônica, em que a síntese de nanopartículas, a fabricação de guias de onda e a caracterização óptica não-linear foram realizadas.

<p>This thesis considers integration of antennas and active electronics manufactured on the same substrate. The main topic is on-chip antennas for commercial silicon processes, but hybrid integration using printed circuit board technology is also addressed.</p><p>The possible use of micromachining techniques as a means of reducing substrate losses of antennas manufactured on low resistivity silicon wafers is investigated. Compact dipole, loop, and inverted-F antennas for the 20-40 GHz frequency range are designed, implemented, and characterized. The results show significantly improved antenna efficiency when micromachining is used as a post-processing step for on-chip antennas manufactured in silicon technology.</p><p>High resistivity wafers are used in a commercial silicon germanium technology to improve the efficiency of dipole antennas realized using the available circuit metal layers in the process. Monolithically integrated 24 GHz receivers with on-chip antennas are designed and evaluated with regard to antenna and system performance. No noticeable degradation of the receiver performance caused by cross talk between the antenna and the integrated circuit is observed.</p><p>For low frequency antenna arrays, such as base station antennas, hybrid integration of active devices within the antenna aperture is treated. A compact varactor based phase shifter for traveling wave antenna applications is proposed and evaluated. Electrically steerable traveling wave patch antenna arrays, with the phase shifters implemented in the same conductor layer as the radiating elements, are designed and manufactured in microstrip technology. It is experimentally verified that the radiation from the feed network and phase shifters in the proposed antenna configuration is small.</p>