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Orientador: José Maria Campos dos Santos Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica Resumo: Os ressonadores de Helmholtz foram utilizados amplamente na engenharia acústica como dispositivos passivos para reduzir o ruído em bandas de freqüência estreitas. Nas últimas décadas, algumas abordagens foram propostas para melhorar o desempenho do ressonador de Helmholtz. Muitos deles se concentram em ajustar a freqüência de ressonância para ampliar a largura de banda de ressonância e melhorar a perda de transmissão sonora. Para ampliar a largura de banda de freqüência, as configurações do ressonador Helmhlotz dispostos periodicamente são propostas. Uma abordagem interessante e promissora para obter uma ampla faixa de atenuação em um duto consiste em distribuir ressonadores locais de Helmholtz periodicamente ao longo do duto. Isso gera algumas bandas de freqüência, conhecidas como "bandas de parada"ou "bandgaps", onde as ondas harmônicas não se propagassem. Os Bandgaps comumente estudados na área de cristais fononicos e metamateriais são gerados com base na frequência espacial das áreas de impedância incompatíveis que produzem efeito de dispersão de Bragg e efeito de ressonância local dos ressonadores de Helmholtz. Este trabalho investiga as lacunas de banda criadas no sistema de duto-ressonador utilizando o método da matriz de transferência acústica (TMM) e os modelos de elementos finitos de onda (WFE). As variações periódicas da geometria são investigadas. O teorema de Floquet-Bloch é usado em uma matriz de transferência da célula periódica rearranjada de uma matriz de rigidez dinâmica acústica para obter os diagramas de dispersão que revelam os intervalos da banda causados pela dispersão de Bragg. As previsões numéricas da resposta forçada obtida pelo modelo de elementos finitos (FE) de um sistema duto-ressonador com três células são comparados com o modelo de elementos finitos de onda (WFE) Abstract: Helmholtz resonators have been used extensively in acoustic engineering as passive devices to reduce noise in narrow frequency bands. In the last decades, some approaches have been proposed to improve the performance of Helmholtz resonator. Many of them concentrate on tuning the resonance frequency to enlarge the resonance bandwidth and improve the transmission loss. To broaden the frequency bandwidth, configurations of Helmhlotz resonator in array are proposed. An interesting and promising approach to obtain a broader attenuation range in a duct consists in to distribute local resonators branch-side type with Helmholtz resonators periodically along the duct. This generates some frequency bands, known as "stop bands" or "band gaps", were harmonic waves do not propagate. Bandgaps commonly studied in the area of phononic crystals and metamaterials are generated based on the spatial frequency of mismatched impedance areas which produce Bragg scattering effect and local resonance effect from the Helmholtz resonators. This work investigates the band gaps created in duct-resonator system using acoustic transfer matrix method (TMM) and finite element models (FEM) models. Periodic geometry variations are investigated. The Floquet-Bloch theorem is used on a transfer matrix of the periodic cell rearranged from an acoustic dynamic stiffness matrix to obtain the dispersion diagrams that reveal the band gaps caused by Bragg scattering and local resonance. Numerical predictions of the forced response obtained with the full FEM model of a duct-resonators system with three cells are compared with a (WFE) Mestrado Mecânica dos Sólidos e Projeto Mecânico Mestre em Engenharia Mecânica CAPES 33.00.30.17

Orientador: Rui Fragassi Souza Tese (doutorado) - Universidade Estadual de Campinas. Faculdade de Engenharia Eletrica e de Computação Resumo: Esta tese trata da comunicação quântica, interferométrica e polarimétrica, em redes ópticas. Inicialmente usa-se a discretização de modos contínuos e o operador de.Pegg­Barnett para a obtenção das funções densidade de probabilidade, do número de fótons e da fase, de um estado coerente, a partir da envoltória do campo. Estas são calculadas numericamente em uma simulação do tipo Monte Carlo. O método é usado na simulação do protocolo quanto-criptográfico BB84 em um interferômetro a fibra óptica. Em seguida, propomos um equalizador óptico, estrutura fisica e algoritmo de equalização, para corrigir a variação da polarização devido à propagação na fibra óptica. Defrnimos, também, o grau de pureza para estados quânticos e encontramos sua relação com os conceitos mais comuns da teoria quântica da informação, como entropia quântica, fidelidade e informação mútua. Completamos descrevendo os estados quânticos entrelaçados e as medidas de entrelaçamento. Por fim, apresentamos o ressonador não-linear a fibra, RNL, o acoplador não-linear a fibra, ANL, e o efeito de birrefringência em fibra no regime não-linear. Em particular, mostramos a possibilidade de controle e sincronização de RNLs usando controladores nebulosos, bem com a possibilidade de variação da curva de transmissividade do ANL com a variação do perfil da constante de acoplamento. Aproveitamos as características destes dispositivos em comunicações quânticas Abstract: This thesis deals with interferometric and polarimetric quantum communication in optical networks. We span from quantum optics till set ups of optical communications systems using non-linear optical devices, inc1uding the math behind the quantum information theory. We start using continuous mode discretization and the Pegg-Bamett phase operator in a method to obtain both the photon number and the phase probability density functions, of a coherent state, from the electric field envelope. Then, we apply the method in a simulation of the quantum-cryptographic protocol BB84, in a lossy and dispersive fibre interferometer. In continuation, an optical equaliser, with its structure and equalisation algorithm, is proposed in order to correct the scrambled polarisation due to the propagation in the fibre. After this, we define the degree of purity for quantum states, in a two-dimensional Hibert space, and we find out its relationship with the quantum entropy. Then, we attack the most common quantum information concepts as quantum distinguishability, fidelity and mutual information using the degree of purity. At last, we describe the quantum entanglement and the most common measure entanglement. Finally, we show, using numerical simulations, the behaviour of a non-linear fiber resonator, RNL, of a non-linear fibre coupler, ANL, and of the fibre birefringence effect in non-linear regime. In particular, we demonstrate the possibility of control and synchronization of RNLs with fuzzy controllers, as well as the possibility of changing the transmissivity curve of an ANL with the variation of its coupler coefficient profile. We apply those non-linear devices in quantum communications systems Doutorado Doutor em Engenharia Elétrica

Orientador: Newton Cesário Frateschi Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin Resumo: O objetivo principal desta tese foi buscar materiais que pudessem gerar ganho óptico por emissão estimulada usando como base o silício e, consequentemente, usar estes materiais em dispositivos fotônicos. A base de emissão ativa usada neste trabalho foi o Silício Amorfo dopado com íons de terra rara, Érbio, (a-Si) com emissão de luz característica na região da banda C usada em telecomunicações ópticas ( ~1550 nm ). O trabalho mostra o desenvolvimento e a evolução da emissão em 1550 nm em diversas condições de fabricação de a-Si, passando por sua oxigenação, criação de nanocristais de silício e com o desenvolvimento de estruturas ressonantes. Com estas amostras sugerimos e fabricamos estruturas compatíveis com tecnologia de Silício tais como microdisco suspensos de Silício e cristais fotônicos bidimensionais baseados em membranas suspensas. Os resultados obtidos ao longo desta tese mostram a viabilidade do uso de íons de Er3+ como dopantes em Si para estas aplicações específicas pois conseguimos aumentar a emissão em 1550 nm destes materiais em mais de 135 mil vezes e também propusemos, experimentalmente, estruturas fotônicas passíveis de se ter ganho, ou seja, que demonstram indícios de emissão estimulada, com estes materiais abrindo caminho, para o uso do Érbio em tecnologias de fotônica de silício Abstract: The main goal of this work was to find materials that could generate stimulated optical gain based on silicon, and, consequently, use these materials in photonic devices. The sample structure used for this work was amorphous silicon doped with earth rare ions, Erbium (a- Si) with characteristic light emission in the C-band region used in telecommunication (~1550nm). The work shows the development and evolution of the 1550nm emission in many a-Si fabrication conditions, from oxygenation, silicon nano-crystals formation, to the development of resonant structures. With these samples, we have fabricated with these material that were compatible with Silicon technology such as Silicon microdisks and active bidimensional photonic crystal resonator membrane. The results suggest the viability of the use of Er3+ ions as dopant in Si for these specific applications since we were able to increase the 1550nm emission of these materials in over 135 thousand times. We also proposed, experimentally, photonic structures that could generate gain, meaning that they have shown signs of stimulated emission opening a path for the use of Erbium in silicon photonic technologies Doutorado Física Doutor em Ciências

Orientadores: Yuzo Iano, Leonardo Lorenzo Bravo Roger Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação Resumo: Este trabalho apresenta o desenvolvimento de um novo ressonador de tipo loop para Frequency Selective Surface (FSS) com a intencao de usa-lo em tags chipless de Radiofrequency Identification (RFID). O ressonador e concebido usando um fractal de Koch invertido de primeira ordem, com a caracteristica geometrica de poder variar o angulo principal do fractal mantendo o comprimento total do perimetro, o que permite manter o comprimento eletrico do ressonador e, em consequencia, manter a frequencia de ressonancia do modelo quase constante. Este comportamento permite niveis apreciaveis de miniaturizacao do ressonador proposto em comparacao ao ressonador quadrado de tipo loop, o qual se torna um caso especial da nossa proposta. O ressonador proposto foi projetado sobre uma superficie Higth Impedance Surface (HIS) o que permite seu uso em aplicacoes de tags chipless de RFID. Foram projetados e simulados varios modelos de ressonadores e multiressonadores (varios ressonadores aninhados) em arranjos de 1x1, 3x1, 3x3, 3x2 mostrando seu potencial para aplicacoes de RFID chipless. Todos os modelos foram construidos e medidos na banda de 7 a 10 ...... em uma guia de onda ..112 mostrando grandes niveis de similitude entre as respostas simuladas e medidas. Tambem foram realizados estudos de multifisica para mostrar a importancia e capacidade de este tipo de estudo na aceleracao do processo de desenvolvimento de sensores tags chipless, dadas as possibilidades que da este tipo de estudo para projetar dispositivos nos que suas respostas possa se correlacionar com as variaveis de interesse a sensar Abstract: This work presents the development of a new loop type resonator for FSS with the intention of being used in RFID tags chipless. The resonator is projected using a first order inverted Koch fractal, with the geometrical particularity of being able to vary the main angle of the fractal maintaining the total length of the perimeter, which allows to maintain the electrical length of the resonator and consequently to maintain almost constant the resonance frequency of the model. This behavior allows obtaining significant levels of miniaturization of the proposed resonator with respect to the square loop type resonator, which also becomes a particular case of our proposal. The resonator was projected on a HIS surface allowing it to be used in applications of RFID tags chipless. Several models of individual resonators and also multiresonators (several nested resonators) were projected and simulated in 1x1, 3x1, 3x3, and 3x2 arrays showing their potential for chipless RFID applications. All models were also constructed and measured in the 7 to 10 GHz band in a waveguide W112 showing large levels of similarity between the simulated responses and the measurements. We also carried out mutiphysical studies to demonstrate the importance and capacity of this type of studies in the acceleration of projects of sensors of tags chipless, given the possibilities that they offer to project devices in which their answers can be correlated with variables of interest to sensing Doutorado Telecomunicações e Telemática Doutor em Engenharia Elétrica CAPES 15267121

Orientador: Newton Cesário Frateschi Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin Resumo: Esta tese de doutorado apresenta resultados experimentais do crescimento de pontos quânticos de InAs diretamente sobre InGaAsP de baixa energia de bandgap (?g=1420 nm), cujo desenvolvimento visa a obtenção de um meio ativo com emissão na banda C (1520¿1570 nm) para a fabricação de ressonadores de microdisco. Baseado em resultados de fotoluminescência e microscopia de força atômica, o fenômeno da inter-difusão de elementos na interface InAs/InGaAsP é proposto e calculado, indicando a presença de Gálio e Fósforo na composição dos pontos quânticos. O ganho óptico de pontos quânticos de InAs crescidos sobre InGaAsP é também calculado com base nos resultados obtidos na análise de inter-difusão. Subseqüentemente, a teoria dos modos ressonantes no microdisco, particularmente os modos chamados whispering gallery modes (WGMs), é desenvolvida com o intuito de auxiliar os cálculos de fator de qualidade, fator de confinamento e corrente de limiar. Uma estrutura multicamada (diodo PIN) com região ativa baseada em pontos quânticos do sistema InAs/InGaAsP foi crescida por epitaxia de feixe químico (CBE) para a fabricação de ressonadores de microdisco. A fabricação dos microdiscos é feita por litografia óptica, corrosão por plasma de íons e ataque químico seletivo de InP. Feixe de íons focalizados (FIB) foi usado para substituir o ataque por plasma para diminuir a rugosidade das paredes dos discos. Os ressonadores de microdiscos são caracterizados elétrica e opticamente e os resultados são confrontados com base nos resultados teóricos apresentados ao longo da tese. Com base nos resultados das caracterizações eletro/ópticas dos ressonadores, correções como a inclusão de perdas ópticas da rugosidade da borda e aquecimento local foram acrescidas ao modelo teórico, resultando em boa concordância com os resultados experimentais. Por fim, apresentamos o desenvolvimento de dispositivos híbridos a partir de polímeros orgânicos depositados diretamente sobre microdiscos de InGaAs com o objetivo de integrar meio ativo orgânico com ressonadores inorgânicos para aplicações em optoeletrônica. Estes resultados foram obtidos durante o programa de doutorado com estágio no exterior no Laboratório Nacional de Nanotecnologia (NNL) vinculado à Università del Salento (Lecce/Itália) Abstract:This doctorate¿s thesis presents the growth of InAs quantum dots directly on high bandgap InGaAsP (?g=1420 nm) barriers to be used as the active region of microdisk resonators with emission in the C-band (1520¿1570 nm). Based on photoluminescence and atomic force microscopy experiments, the occurrence of inter-diffusion on the InAs/InGaAsP interface is calculated, suggesting the presence of Gallium and Phosphorus in the quantum dots (QDs) composition. Based also on the inter-diffusion results, the optical gain of the InAs QDs is calculated. Subsequently, microdisk resonator whispering gallery modes (WGMs) are calculated and employed to predicting the cavity quality and confinement factors, as well as the threshold current. A PIN diode with an active region based on InAs QDs was grown by Chemical Beam Epitaxy (CBE) for the fabrication of current injected microdisk resonators. Microdisk fabrication process is performed using photolithography, reactive ion etching and InP selective wet-etching. Focused ion beam is used to replace the plasma etching in order to reduce the roughness of the disk¿s edge. Microdisks resonators are characterized electrically and optically and the measurements are analyzed based on the theoretical results presented along this thesis. Based on these measurements, optical losses caused by disk¿s edge roughness and local heating are added to our simulation tool, resulting in better agreement with the experimental results. Finally, we present the development of hybrid resonators using organic polymer deposited directly on inorganic microdisks integrating an organic active medium with inorganic resonators for optoelectronic applications. These results were obtained during our work at the National Nanotechnology Laboratory (NNL) and the University of Salento (Lecce/Italy) Doutorado Física da Matéria Condensada Doutor em Física

Orientador: Leonardo Lorenzo Bravo Roger Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Tecnologia Resumo: O projeto e a análise teórico-experimental de uma nova etiqueta sem chip para RFID com comunicação redundante é apresentado. Esta nova etiqueta poderá ser capaz de operar em duas bandas de frequências diferentes para a transmissão da informação binária, aproveitando a utilização em sua concepção de antenas dual-band. A técnica aqui mencionada é clássica, conhecida como diversidade de frequência, mas é utilizada neste trabalho pela primeira vez aplicada em etiquetas chipless de RFID visando aumentar a confiabilidade da comunicação com as leitoras de RFID. Simulações realizadas do novo dispositivo proposto com o software HFSS (High Frequency Structural Simulator) mostraram o seu desempenho adequado. A metodologia do projeto é apresentada passo a passo e os resultados são analisados e discutidos no texto Abstract: The project and the theoretical-experimental analysis of a new chipless RFID tag with redundant communication is presented. This new tag may be capable to operate in two different frequencies bands for the transmission of binary information, taking advantage of the use in its design of dual-band antennas. The technique mentioned here is classic, known as frequency diversity, but it is used in this work for the first time applied in chipless RFID tags to increase the reliability of the communication with the RFID readers. Simulations of the proposed new device with HFSS (High Frequency Structural Simulator) software showed an adequate performance. The project methodology is presented step by step and the results are analyzed and discussed in the text Mestrado Tecnologia e Inovação Mestre em Tecnologia

Agradecimentos: The authors would like to acknowledge CCSNano-UNICAMP for providing the micro-fabrication infrastructure and CMC Microsystems for providing access to MBE epitaxy and the GaAs wafers. This work was supported by the São Paulo Research Foundation (FAPESP) through Grant Nos. 2019/09738-9, 2020/06348-2, 2017/14920-5, 2016/18308-0, 2017/19770-1, 2018/15580-6, 2018/15577-5, and 2018/25339-4; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior-Brasil (CAPES) (Finance Code No. 001); Conselho Nacional de Desenvolvimento Científico e Tecnológico through Grant Nos. 425338/2018-5, 310224/2018-7, and 465469/2014-0; Financiadora de Estudos e Projetos (Finep); and the Natural Sciences and Engineering Research Council (NSERC) of Canada Abstract: Photothermal effects have been pointed out as prominent sources of forces in optomechanical systems, competing with the standard radiation pressure interactions. In this article, we derive a novel and accurate model for the prediction of photothermal forces and establish how some previous proposals can be complemented to yield precise results. As a proof-of-concept, we perform numerical and experimental tests on GaAs microdisk cavities and obtain striking agreement with our framework, revealing the importance of considering surface photothermal forces and the effects of multiple thermal modes in microphotonic devices FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FINANCIADORA DE ESTUDOS E PROJETOS - FINEP Aberto

Agradecimentos: The authors acknowledge CCSNano-UNICAMP for providing the micro-fabrication infrastructure and CMC Microsystems for providing access to MBE epitaxy and the GaAs wafers. This work was supported by the São Paulo Research Foundation (FAPESP) under Grant Nos. 2017/19770-1, 2016/18308-0, 2018/15580-6, 2018/15577-5, and 2018/25339-4, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Brasil (Finance Code 001), the Financiadora de Estudos e Projetos, and the National Sciences and Engineering Research Council (NSERC) of Canada Abstract: The integration of optomechanics and optoelectronics in a single device opens new possibilities for developing information technologies and exploring fundamental phenomena. Gallium arsenide (GaAs) is a well-known material that can bridge the gap between the functionalities of optomechanical devices and optical gain media. Here, we experimentally demonstrate a high-frequency GaAs optomechanical resonator with a ring-type bullseye geometry that is unprecedented in this platform. We measured mechanical modes up to 3.4 GHz with quality factors of 4000 (at 80 K) and optomechanical coupling rates up to 39 kHz at telecom wavelengths. Moreover, we investigated the material symmetry break due to elastic anisotropy and its impact on the mechanical mode spectrum. Finally, we assessed the temperature dependence of the mechanical losses and demonstrated the efficiency and anisotropy resilience of the bullseye anchor loss suppression, indicating that lower temperature operation may allow mechanical quality factors over 10(4). Such characteristics are valuable for active optomechanics, coherent microwave to optics conversion via piezomechanics, and other implementations of high-frequency oscillators in III-V materials FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FINANCIADORA DE ESTUDOS E PROJETOS - FINEP Aberto

The shaping of group velocity dispersion in microresonators is an important component in the generation of wideband optical frequency combs. Small resonators-with tight bending radii-offer the large free-spectral range desirable for wide comb formation. However, the tighter bending usually limits comb formation as it enhances normal group velocity dispersion. We experimentally demonstrate that engineering the sidewall angle of a small-radius (similar to 100 mu m), 3-mu m-thick silica wedge microdisk enables dispersion tuning in both normal and anomalous regimes, without significantly affecting the free spectral range. A microdisk with a wedge angle of 55 degrees (anomalous dispersion) is used to demonstrate a 300 nm bandwidth Kerr optical frequency comb FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FINANCIADORA DE ESTUDOS E PROJETOS - FINEP Fechado

Orientadores: Leandro Tiago Manera, Newton Cesário Frateschi Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação Resumo: Lasers de microdiscos apresentam um alto confinamento do modo ótico na região de ganho, uma baixa potência limiar e facilidade de integração. Essas características os fazem apropriados como fontes de luz no desenvolvimento de circuitos integrados fotônicos. Etapas prévias ao desenvolvimento desse tipo de lasers são a fabricação do microdisco e a sua caracterização como ressonador passivo e ativo. Os modos ressonantes no microdisco são chamados de Whispering Gallery Modes (WGM) e propagam-se na sua borda. Neste trabalho, fabricaram-se dois tipos de microdiscos de GaAs, que diferenciam-se no tipo de interface da sua borda: GaAs/ar e GaAs/AlOx. O AlOx é obtido da oxidação úmida de ligas Al0.9Ga0.1As previamente caracterizada. A caracterização como ressonador passivo foi realizada por meio da técnica de acoplamento com fibra afunilada, e, como ressonador ativo, utilizando-se o método de micro fotoluminescência por meio da injeção de portadores ao poço quântico de In0.2Ga0.8As, localizado no meio do GaAs. Os resultados da caracterização como ressonador passivo foram obtidos para os microdiscos de 10 µm de diâmetro e mostraram que os de interface GaAs/ar apresentam um fator de qualidade de aproximadamente o dobro do que os de interface GaAs/AlOx. Baseando-nos no modelamento analítico do microdisco, determinou-se que os modos propagados eram WGM TE. Os resultados da caracterização como ressonador ativo foram obtidos para os microdiscos de 40 µm de diâmetro, e mostraram uma relação entre os picos da emissão do poço quântico e da emissão do GaAs de 3 para os microdiscos com interface GaAs/ar e de 2 para os com interface GaAs/AlOx. A propagação somente dos modos WGM TE nos microdiscos de 10 µm de diâmetro pode sugerir a presença de rugosidades nas paredes laterais, que atenuam a propagação dos modos WGM TM nesses microdiscos e a propagação dos modos WGM TE em microdiscos de maior diâmetro. O menor fator de qualidade para os microdiscos de GaAs/AlOx indicaria que a oxidação produz uma rugosidade adicional nos microdiscos. A menor relação entre os picos do poço e do GaAs para os microdiscos de GaAs/AlOx pode sugerir um aumento das perdas de recombinação superficial do GaAs durante o processo de oxidação. Conseguiu-se a fabricação de microdiscos com interface GaAs/AlOx sem a degradação da camada de GaAs e do poço quântico, mas durante a formação de AlOx introduzem-se rugosidades e defeitos que degradam a qualidade dos microdiscos como ressonadores em relação aos microdiscos com interface GaAs/ar Abstract: Microdisk lasers have a high confinement of the optical mode in the gain region, a low threshold power and ease of integration. These characteristics make them suitable as light sources in the development of photonic integrated circuits. Previous steps to the development of this type of lasers are the fabrication of the microdisk and its characterization as a passive and active resonator. The resonant modes on the microdisk are called Whispering Gallery Modes (WGM) and propagate at its edge. In this work, two types of GaAs microdisks were fabricated, which differ in the interface type of their edge: GaAs/air and GaAs/AlOx. AlOx is obtained from the wet oxidation of previously characterized Al0.9Ga0.1As alloys. The characterization as a passive resonator was performed using the tapered fiber coupling technique, and, as an active resonator, using the micro photoluminescence method by injecting carriers into the In0.2Ga0.8As quantum well, located in the middle of GaAs. The results of the characterization as a passive resonator were obtained for the microdisks of 10 µm in diameter and showed that those of the GaAs/air interface have a quality factor of approximately twice that of the GaAs/AlOx interface. Based on the analytical modeling of the microdisk, it was determined that the propagated modes were WGM TE. The results of the characterization as an active resonator were obtained for the microdisks of 40 µm in diameter, and showed a relationship between the peaks of the quantum well emission and the GaAs emission of 3 for the microdisks with GaAs/air interface and 2 for the with GaAs/AlOx interface. The propagation of only the WGM TE modes in microdisks of 10 µm in diameter may suggest the presence of roughness in the sidewalls, which attenuate the propagation of WGM TM modes in these microdisks and the propagation of WGM TE modes in microdisks of larger diameter. The lowest quality factor for GaAs/AlOx microdisks would indicate that oxidation produces additional roughness in the microdisks. The lower relationship between the well peaks and the GaAs for the GaAs/AlOx microdisks may suggest an increase in the losses of GaAs surface recombination during the oxidation process. It was possible to manufacture microdisks with a GaAs/AlOx interface without the degradation of the GaAs layer and the quantum well, but during the formation of AlOx, roughness and defects are introduced that degrade the quality of microdisks as resonators in relation to microdisks with an interface GaAs/air Mestrado Telecomunicações e Telemática Mestre em Engenharia Elétrica CAPES 001

Simulation data are presented for identifying and analysing the dynamic properties of the rainbow metamaterials as presented in the articles “Rainbow metamaterials for broadband multi-frequency vibration attenuation: numerical analysis and experimental validation” (Meng et al., 2019 [1]) and “Optimal design of rainbow elastic metamaterials” (Meng et al., 2019 [2]). In this data article, the frequency response functions and mode shapes of the rainbow metamaterials are numerically calculated by Finite Element models set up in Ansys Mechanical APDL. Harmonic analysis was performed to figure out the receptance function values of the rainbow metamaterials within the frequency regime 0–500 Hz. Modal analysis was applied to estimate the mode shapes, which could be used to explain the critical peaks and dips in the receptance function curve. Source files of Finite Element models are provided in the data. The Finite Element simulation is not only an effective alternative way to estimate the dynamic properties of the rainbow metamaterials, the mode shape analysis, which is unlikely to be achieved with the analytical model, provides direct insights into the underlying vibration mechanism of the rainbow metamaterials.

Agradecimentos: This work was supported by Australian Research Council Grant No. CE170100009 and a UWA Research Collaboration Award with IMT-Atlantique Abstract: We demonstrate the generation of coherent phonons in a quartz bulk acoustic wave (BAW) resonator through the photoelastic properties of the crystal, via coupling to a microwave cavity enhanced by a photonic lambda scheme. This is achieved by imbedding a single crystal BAW resonator between the post and the adjacent wall of a microwave re-entrant cavity resonator. This 3D photonic lumped LC resonator at the same time acts as the electrode of a BAW phonon resonator and allows the direct readout of coherent phonons via the linear piezoelectric response of the quartz. A microwave pump, omega(p), is tuned to the cavity resonance omega(0), while a probe frequency, omega(probe), is detuned and varied around the red and blue detuned values with respect to the BAW phonon frequency, Omega(m). The pump and probe power dependence of the generated phonons unequivocally determines the process to be electrostrictive, with the phonons produced at the difference frequency between the pump and the probe, with no back action effects involved. Thus, the phonons are created without threshold and can be considered analogous to a passive coherent population trapped maser scheme Fechado

A method to fabricate GaAs microcavities using only a soft mask with an electrolithographic pattern in an inductively coupled plasma etching is presented. A careful characterization of the fabrication process pinpointing the main routes for a smooth device sidewall is discussed. Using the final recipe, optomechanical microdisk resonators are fabricated. The results show very high optical quality factors of Q(opt) > 2 x 10(5), among the largest already reported for dry-etching devices. The final devices are also shown to present high mechanical quality factors and an optomechanical vacuum coupling constant of g(0) = 2 pi x 13.6 kHz enabling self-sustainable mechanical oscillations for an optical input power above 1 mW FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Aberto

Agradecimentos: We thank A. Bachtold for discussions. This work was supported in part by the National Science Foundation under grant number 0928552. It was also supported by the Cornell Center for Materials Research with funding from the NSF MRSEC programme (DMR-1719875) and funding from IGERT (DGE-0654193). This work was performed in part at the Cornell NanoScale Facility, a member of the National Nanotechnology Coordinated Infrastructure (NNCI), which is supported by the National Science Foundation (Grant ECCS-1542081). G.S.W. acknowledges FAPESP (grant 2012/17765-7) and CNPq for financial support in Brazil Abstract: The field of miniature mechanical oscillators is rapidly evolving, with emerging applications including signal processing, biological detection(1) and fundamental tests of quantum mechanics(2). As the dimensions of a mechanical oscillator shrink to the molecular scale, such as in a carbon nanotube resonator(3-7), their vibrations become increasingly coupled and strongly interacting(8,9) until even weak thermal fluctuations could make the oscillator nonlinear(10-13). The mechanics at this scale possesses rich dynamics, unexplored because an efficient way of detecting the motion in real time is lacking. Here we directly measure the thermal vibrations of a carbon nanotube in real time using a high-finesse micrometre-scale silicon nitride optical cavity as a sensitive photonic microscope. With the high displacement sensitivity of 700 fm Hz(-1/2) and the fine time resolution of this technique, we were able to discover a realm of dynamics undetected by previous time-averaged measurements and a room-temperature coherence that is nearly three orders of magnitude longer than previously reported. We find that the discrepancy in the coherence stems from long-time non-equilibrium dynamics, analogous to the Fermi-Pasta-Ulam-Tsingou recurrence seen in nonlinear systems(14). Our data unveil the emergence of a weakly chaotic mechanical breather(15), in which vibrational energy is recurrently shared among several resonance modes-dynamics that we are able to reproduce using a simple numerical model. These experiments open up the study of nonlinear mechanical systems in the Brownian limit (that is, when a system is driven solely by thermal fluctuations) and present an integrated, sensitive, high-bandwidth nanophotonic interface for carbon nanotube resonators CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: This work is supported by the U.S. Government under ARO Grants No. W911NF-14-1-0080 and No. W911NF15-1-0248. Device fabrication is performed at the Cornell NanoScale Facility, a member of the National Nanotechnology Coordinated Infrastructure (NNCI), which is supported by the National Science Foundation (Grant No. NNCI-1542081). A.P.Z. acknowledges support from Volkswagen Foundation (Grant No. 90284). B.G.T. acknowledges support from FAPESC, CNPq and the National Institute for Science and Technology - Quantum Information. A.V.U. acknowledges partial support from the German Science Foundation (Grant No. US18/15-1), the Russian Science Foundation (Grant No. 16-12-00095), and the Ministry of Education and Science of Russian Federation in the framework of the Increase Competitiveness Program of the National University of Science and Technology MISIS (Grant No. K2-2017-081) Abstract: Superconducting metamaterials are a promising resource for quantum-information science. In the context of circuit QED, they provide a means to engineer on-chip dispersion relations and a band structure that could ultimately be utilized for generating complex entangled states of quantum circuitry, for quantum-reservoir engineering, and as an element for quantum-simulation architectures. Here we report on the development and measurement at millikelvin temperatures of a particular type of circuit metamaterial resonator composed of planar superconducting lumped-element reactances in the form of a discrete left-handed transmission line that is compatible with circuit QED architectures. We discuss the details of the design, fabrication, and circuit properties of this system. As well, we provide an extensive characterization of the dense mode spectrum in these metamaterial resonators, which we conduct using both microwave-transmission measurements and laser-scanning microscopy. Results are observed to be in good quantitative agreement with numerical simulations and also an analytical model based upon current-voltage relationships for a discrete transmission line. In particular, we demonstrate that the metamaterial mode frequencies, spatial profiles of current and charge densities, and damping due to external loading can be readily modeled and understood, making this system a promising tool for future use in quantum-circuit applications and for studies of complex quantum systems CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA E INOVAÇÃO DO ESTADO DE SANTA CATARINA - FAPESC Fechado

Agradecimentos: We acknowledge fruitful discussions with R. Benevides and T. P. M. Alegre. This research was supported by the Australian Research Council, No. CE170100009, and by the CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO (CNPq-Brazil) Abstract: We report the observation of coupling between a 3D microwave cavity mode and a bulk mechanical resonator mediated by piezoelectric and radiation pressure effects. The system is composed of a quartz bulk acoustic wave resonator placed inside a microwave re-entrant cavity, which is designed to act as both the electrodes for piezoelectric actuation and a 3D resonator. The cavity electromagnetic mode is modulated by a 5 MHz bulk acoustic wave shear mode, which is modeled and experimentally verified using the input-output formalism. Through finite element method simulations, we calculate the various contributions to the electromechanical coupling and discuss the potential of the system to reach high cooperativities as well as suitable applications CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológio, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2009 Os tubos ressonantes são elementos acústicos reativos de absorção sonora, sintonizáveis em frequências múltiplas ou específicas. Estes podem ser aplicados para o controle de ruído em dutos, cavidades e filtros acústicos, como por exemplo, mufflers de compressores. A atenuação sonora proporcionada pelos absorvedores reativos geralmente é fornecida por mecanismos de reflexão atribuídos a variações bruscas na impedância acústica, associada ao acoplamento acústico das geometrias. As perdas por efeitos viscosos e térmicos no interior dos dutos são fatores importantes na absorção sonora, as quais devem ser levadas em consideração, necessitando-se assim um estudo aprofundado destes efeitos. A vantagem dos tubos ressonadores em relação ao ressonador de Helmholtz é a possibilidade de sintonização em múltiplas freqüências, o fato de sua aplicação ser robusta, não havendo a perda de suas características acústicas com o tempo, como ocorre com os materiais porosos impregnados de óleo. Para se entender as características de atenuação sonora dos tubos ressonantes em dutos, filtros acústicos e cavidades, realizou-se uma pesquisa através de procedimentos experimentais, modelos analíticos e computacionais. Com o objetivo de otimizar a atenuação dos tubos ressonantes, aplicaram-se métodos de otimização aos modelos analíticos de filtros de geometria simplificada e dutos, em relação aos parâmetros de dimensionamento e aplicação. Estes modelos foram comparados numericamente e experimentalmente através de avaliações feitas a partir da função resposta em freqüência, que representa a razão entre a pressão sonora medida na saída e na entrada da geometria analisada. Por fim, avaliou-se numericamente e experimentalmente a capacidade de atenuação sonora de tubos ressonantes aplicados em cavidades. Desta forma, pôde ser feita uma análise crítica dos resultados obtidos. Conclui-se que é possível obter boa atenuação do ruído aplicando-se tubos ressonantes em dutos, mufflers e cavidades. Apesar das limitações do modelo analítico, das incertezas experimentais e os erros numéricos, os modelos se mostram concordantes, tornando-se ferramentas eficientes de análise de materiais de absorção sonora.

Dissertação de Mestrado Integrado em Engenharia Física apresentada à Faculdade de Ciências e Tecnologia Circuitos supercondutores quânticos oferecem um leque abrangente de aplicações em campos como a computação quântica, com qubits supercondutores, detecção de radiação na forma de detectores de indutância cinética (KIDs). Estes circuitos são compostos por filmes finos de materiais supercondutores, como Alúminio, depositados sobre um substrato dieléctrico, como silício ou safira, e funcionam a temperaturas criogénicas de algumas dezenas de mili-Kelvins. A eficiência destes circuitos pode ser prejudicada pela presença de excitações do estado supercondutor fundamental a que damos o nome de quase-partículas, que criam um canal para dissipação e introduzem ruído no sistema. Neste texto propomos que a propagação de fonões no substrato pode actuar como mediador para a criação destas partículas. Introduzimos também uma estratégia para suprimir este fenómeno implementando traps de fonões, com o objectivo de suprimir a propagação de fonões no substrato. Testamos os efeitos de armadilhas de fonões feitas a partir de Alumínio em ressonadores de Alumínio granulado. E medimos um aumento no factor de qualidade interno de até três vezes, no regime em que apenas um fotão circula os ressonadores. Observamos também a supressão parcial do ruído 1/f e da taxa e energia de eventos estocásticos. Indicando que a criação de quase-partículas é de facto mediada pela propagação de fonões, e que a implementação de armadilhas de fonões pode de facto melhorar o desempenho de circuitos supercondutores quânticos. Superconducting quantum circuits are an active field of research with various applications such as in fault tolerant quantum computation, with superconducting quantum bits showing good performance, and radiation detection, in the form of kinetic inductance detectors (KIDs). These circuits are made of thin films of superconducting materials, such as Aluminum, deposited over a dielectric substrate, such as Silicon or Sapphire, operating at cryogenic temperatures of a few tens of mili-Kelvin. Their efficiency can be degraded by the presence of excitations of the superconducting ground state called quasi-particles which behave mostly like electrons. They add a channel for dissipation and introduce noise to the system. In this text we propose, that phonon propagation in the substrate can act as a mediator for the creation of these quasi-particles, and introduce a strategy to suppress this phenomena by implementing phonon traps. We tested the effects of Aluminum phonon traps in granular Aluminum resonators and measured an increase of internal quality factor in the single photon regime of up to a factor of three. We also observed a partial suppression of 1/f noise and of rate and maximum energy of stochastic bursts, indicating that quasi-particle creation is in fact partially mediated by phonon propagation in the substrate, as hypothesized, and that the implementation of phonon traps is an efficient, easy to implement way of improving the performance of superconducting quantum circuits.

Agradecimentos: The authors would like to thank Y. A. V. Espinel for the support with the FEM simulations and T. P. M. Alegre for useful insights Abstract: We developed a model for an active optomechanical cavity embedding a semiconductor optical gain medium in the presence of dispersive and dissipative optomechanical couplings. Radiation pressure drives the mechanical oscillation and the back-action occurs due to the mechanical modulation of the cavity loss rate. Our numerical analysis utilizing this model shows that, even in a wideband gain material, such mechanism couples the mechanical vibration with the laser relaxation oscillation, enabling an effect of self-pulsed laser emission. In order to investigate this effect, we propose a bullseye-shaped device with high confinement of both the optical and the mechanical modes at the edge of a disk combined with a dissipative structure in its vicinity. The dispersive interaction is promoted by the strong photoelastic effect while the dissipative mechanism is governed by the boundary motion mechanism, enhanced by near-field interaction with the absorptive structure. This hybrid optomechanical device is shown to lead sufficient coupling for the experimental demonstration of the self-pulsed emission FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2018. Este trabalho avalia a utilização dos ressonadores isolados ou em conjunto com os materiais porosos para o tratamento termoacústico de painéis duplos. Para a avaliação da perda de transmissão (TL), inicialmente, foi criado um modelo numérico para avaliar a absorção em tubo de impedância dos ressonadores e materiais porosos. Os resultados foram validados utilizando o método das matrizes de transferência (TMM) e o experimento no tubo de impedância. Na sequência foi proposta uma configuração onde o ressonador estava incluso no material poroso. Os resultados obtidos para esta configuração foram comparados com TMM e experimentos. Devido a algumas dúvidas no funcionamento dos ressonadores, criou-se um modelo paramétrico para avaliar a espessura da camada de ar na frente do pescoço do ressonador (t) e a espessura de ar lateral ao pescoço do ressonador (R_ar). Com este modelo foram definidos valores mínimos para t e R_ar para que tivesse funcionamento pleno. Por fim, foram utilizados ressonadores com ou sem material poroso para a determinação da TL de painéis duplos utilizando FEM, TMM e experimento em câmaras reverberantes. Para as análises de TL foram feitas diversas configurações a fim de determinar em qual delas os ressonadores possuem maior influência na resposta da TL dos painéis. Com os resultados obtidos, observou-se que para o modelo numérico a melhor configuração teve um ganho de 10 dB na frequência de sintonia do ressonador, já para o experimento esse ganho foi de aproximadamente 11 dB. Abstract : This work evaluates the use of the resonators alone or in conjunction with the porous materials for the thermoacoustic treatment of double panels. For the evaluation of the transmission loss (TL), initially a numerical model was created to evaluate the absorption in impedance tube of the resonators and porous materials. The results were validated using the transfer matrix method (TMM) and the impedance tube experiment. In the sequence, a configuration was proposed where the resonator was included in the porous material. The results obtained for this configuration were compared with TMM and experiments. Due to some doubts in the operation of the resonators, the parametric model was created to evaluate the thickness of the air layer in front of the resonator neck (t) and the lateral air thickness to the resonator neck (R_ar). With this model, minimum values for t and R_arwere defined for full operation. Finally, the resonators with or without porous material were used for the determination of TL of double panels using FEM, TMM and experiment in reverberant chambers. For the TL analysis several configurations were made in order to determine in which of them the resonators would have greater influence in the TL response of the panels. With the results obtained, it was observed that for the best configuration of numerical model had a gain of 10 dB in the tuning frequency of the resonator, already for the experiment that gain was approximately 11 dB.

Agradecimentos: We would like to thank CNPq (Conselho Nacional para o Desenvolvimento Científico e Tecnológico) and FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo), Brazil, for financial support through the National Institute for Science and Technology of Quantum Information (INCT-IQ under grant 2008/57856-6) and the Optics and Photonics Research Center (CePOF under grant 2005/51689-2) Abstract: We present a scheme for cavity-assisted generation of hybrid entanglement between a moving mirror belonging to an optomechanical cavity and a single trapped ion located inside a second cavity. Due to radiation pressure, it is possible to entangle the states of the moving mirror and the corresponding cavity field. Also, by tuning the second cavity field with the internal degrees of freedom of the ion, an entangled state of the cavity field/ion can be independently generated. The fields leaking from each cavity may be then combined in a beam splitter, and following the detection of the outgoing photons by conveniently placed photodetectors, we show that it is possible to generate entangled states of the moving mirror and the single trapped ion's center-of-mass vibration. In our scheme the generated states are hybrid entangled states, in the sense that they are constituted by discrete (Fock) states and continuous variable (coherent) states CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Aberto

Submitted by Alex Sandro Rêgo (alex@ifpb.edu.br) on 2017-06-06T12:21:00Z No. of bitstreams: 1 34- Josefa Gilliane de Oliveira Mariano - IMPLEMENTAÇÃO DE FILTROS PLANARES BASEADOS NA GEOMETRIA MATRIOSKA.pdf: 2828908 bytes, checksum: 1c0801d52ad64d38cd8011edfc26a340 (MD5) Approved for entry into archive by Alex Sandro Rêgo (alex@ifpb.edu.br) on 2017-06-06T12:34:10Z (GMT) No. of bitstreams: 1 34- Josefa Gilliane de Oliveira Mariano - IMPLEMENTAÇÃO DE FILTROS PLANARES BASEADOS NA GEOMETRIA MATRIOSKA.pdf: 2828908 bytes, checksum: 1c0801d52ad64d38cd8011edfc26a340 (MD5) Made available in DSpace on 2017-06-06T12:34:10Z (GMT). No. of bitstreams: 1 34- Josefa Gilliane de Oliveira Mariano - IMPLEMENTAÇÃO DE FILTROS PLANARES BASEADOS NA GEOMETRIA MATRIOSKA.pdf: 2828908 bytes, checksum: 1c0801d52ad64d38cd8011edfc26a340 (MD5) Previous issue date: 2017-05-06 Os filtros desempenham um papel fundamental nos sistemas de telecomunicações. Embora seja uma das tecnologias mais consolidadas na Engenharia de micro-ondas, o intenso crescimento das aplicações dos sistemas de telecomunicações impõe um desafio constante, requerendo o estudo de novas configurações de filtros e uma melhor compreensão do funcionamento dessas estruturas, em face aos requisitos de miniaturização, baixo custo, largura de banda e seletividade em frequência. Neste contexto, propõe-se neste trabalho a implementação de filtros planares utilizando a geometria matrioska com uma e duas seções. Como exemplos de filtros de uma seção são apresentados os resultados numéricos e experimentais de filtros utilizando a geometria matrioska, com um, dois e três anéis matrioska, observandose uma boa concordância entre esses resultados. São apresentados os resultados numéricos e experimentais de filtros com duas seções, tanto com as mesmas dimensões, como com seções de dimensões diferentes. Além disto, são propostas equações iniciais para as duas primeiras frequências de ressonância, que podem auxiliar no processo de otimização do filtro, fornecendo os valores inicias de projeto. Dentre as características obtidas, destacam-se: dimensões reduzidas, rápida transição da banda passante para a banda de rejeição e ajuste da largura de banda, o que incentiva a continuidade das pesquisas do filtro proposto.

Dielectric ceramics with ordered double perovskite structure and RE2CoMnO6 stoichiometry, in which RE is a rare-earth ion, are usually multiferroic with critical magnetic and electrical transition temperatures depending on the RE ion. This family of materials crystallizes in the P21/n symmetry when there is ordering of the Mn and Co ions. This monoclinic structure has a distortion directly dependent on the RE ionic size, influencing directly the properties of these materials. In this work, we investigate the intrinsic dielectric properties of these samples for RE = Tb, Dy, Ho, Yb and Tm. These properties were investigated by infrared reflection spectroscopy, allowing to estimate both the intrinsic static dielectric constant and the dielectric losses due to the polar phonons, which allows estimating the maximum microwave quality factor obtained when a resonator is formed with the respective materials. Our results show that, as obtained for La2CoMnO6 (LaCMO), the main compound of this family, the intrinsic static dielectric constant is reduced. In the case of LaCMO, dielectric measurements performed by other authors showed a colossal effect, whose origin was extrinsic effects. Therefore, our result allows to predict that any effect that leads to very high dielectric constants is extrinsic in this family of materials. In addition, the analysis of the quality factor showed that such ceramics have a quality factor compatible with those employed in microwave dielectric resonators since the low dielectric constant is not a problem. As cerâmicas dielétricas com estrutura perovskita dupla ordenada com estequiometria RE2CoMnO6, na qual RE é um íon terra-rara, são usualmente multiferróicas com temperaturas críticas de transição magnética e elétrica dependendo do íon RE. Esta família de materiais cristaliza-se na simetria P21/n quando há o ordenamento dos íons Mn e Co. Esta estrutura monoclínica, tem um distorção diretamente ligada ao tamanho do íon RE, o que influencia diretamente suas propriedades. Neste trabalho investigamos as propriedades dielétricas intrínsecas destas amostras para RE = Tb, Dy, Ho, Yb e Tm. Tais propriedades foram investigadas por espectroscopia de reflexão especular no infravermelho, permitindo estimar tanto a constante dielétrica estática intrínseca devido aos fônons polares, como as perdas dielétricas devido a estes fônons, o que permite estimar o fator de qualidade em micro-ondas máximo obtido quando se conforma um ressonador dielétrico com o respectivo material. Nossos resultados mostram que, assim como obtido para o La2CoMnO6 (LaCMO), principal composto desta família, a constante dielétrica estática intrínseca é reduzida. No caso do LaCMO , medidas dielétricas realizadas por outros pesquisadores mostraram efeito colossal, cuja origem eram efeitos extrínsecos. Portanto, nosso resultado permite prever que qualquer efeito que leve a obter constantes dielétricas muito altas tem natureza extrínseca nesta família de materiais. Além disso, a análise do fator de qualidade mostrou que tais cerâmicas tem fator de qualidade compatível com aqueles empregados em ressonadores dielétricos para micro-ondas desde que a constante dielétrica baixa não seja um problema.

Agradecimentos: R.B., G.S.W. and T.P.M.A. designed the devices. R.B. performed the measurements with support from F.G.S.S., G.O.L. and supervision by T.P.M.A., R.B., G.S.W. and T.P.M.A. analyzed the measured data. All authors contributed to the writing of the manuscript Abstract: Photonic crystals use periodic structures to create frequency regions where the optical wave propagation is forbidden, which allows the creation and integration of complex optical functionalities in small footprint devices. Such strategy has also been successfully applied to confine mechanical waves and to explore their interaction with light in the so-called optomechanical cavities. Because of their challenging design, these cavities are traditionally fabricated using dedicated high-resolution electron-beam lithography tools that are inherently slow, limiting this solution to small-scale or research applications. Here we show how to overcome this problem by using a deep-UV photolithography process to fabricate optomechanical crystals in a commercial CMOS foundry. We show that a careful design of the photonic crystals can withstand the limitations of the photolithography process, producing cavities with measured intrinsic optical quality factors as high as Q(i) = (1.21 +/- 0.02) x 10(6). Optomechanical crystals are also created using phononic crystals to tightly confine the GHz sound waves within the optical cavity, resulting in a measured vacuum optomechanical coupling rate of g(0) = 2 pi x (91 +/- 4) kHz. Efficient sideband cooling and amplification are also demonstrated since these cavities are in the resolved sideband regime. Further improvements in the design and fabrication process suggest that commercial foundry-based optomechanical cavities could be used for quantum ground-state cooling FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Aberto

Orientador: Hugo Enrique Hernández-Figueroa Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação Resumo: Este trabalho descreve o desenvolvimento de um sistema de radiofrequência, eficaz e de baixo custo, para identificação de cédulas monetárias e documentos com a intenção de evitar falsificações. O sistema proposto é baseado nas tecnologias de linha de microfita e RFID sem chip, porém, a identificação é feita através do contato do objeto com a leitora. Para que essa identificação ocorra, na leitora, ressoadores em formato espiral são dispostos próximos a uma linha de transmissão, cada ressoador representando um bit de dado, e ressoam livremente até que uma cédula ou documento seja colocada em contato e devidamente alinhada. Cada cédula ou documento deve possuir uma marca metálica impressa em camada interna, pois dificulta falsificações e as ondas eletromagnéticas conseguem atravessar o papel, de forma que cada marca defina o código binário de cada objeto, uma vez que essas marcas metálicas suprimem as ressonâncias dos ressoadores situados na leitora. Em outras palavras, as marcas metálicas transformam o estado do bit de dado, bit 0 ou 1, correspondendo aos estados de presença e ausência de ressonância, respectivamente. O sistema também tem potencial para aumento do volume de codificação de dados com a possibilidade do sistema ternário, quando as ressonâncias possuem três estados. Resultados de simulações e resultados de medições também são apresentados neste trabalho Abstract: This work describes the development of a low-cost and efficient radiofrequency system for banknotes and documents identification intending to avoid counterfeiting. The proposed system is based on the microstrip and chipless RFID technologies; however, the identification is carried out through the contact of the object with the reader. In order to make this possible, the spiral resonators in the reader are placed next to a transmission line, each resonator represents a data bit, they resonate freely until a banknote or a document is placed and aligned properly. Each banknote or document must have a metallic mark printed on its inner layer, because it makes falsification difficult and the electromagnetic waves can cross the paper, in such a way that each metallic mark establishes a binary code. The metallic marks suppress the resonances of the resonators located in the reader. In other words, the marks can change the bits state, 0 or 1, corresponding to the presence and absence of resonance, respectively. The system also has the potential to increase the volume of data encoding with the possibility of the ternary system, when the resonances have three states. Simulation and measurement results are also presented in this work Mestrado Telecomunicações e Telemática Mestre em Engenharia Elétrica CAPES

Agradecimentos: J.K.M. acknowledges financial support from CNPq Grant PDJ 165941/2014-6. M.C.O. acknowledges support by FAPESP through the Research Center in Optics and Photonics (CePOF) and by CNPq. R.P. acknowledges financial support from Faperj (Grant No. E-26/102.350/2013) and CNPq (Grants No. 303406/2015-1 and No. 474143/2013-9) Abstract: The staggered quantum walk is a model defined by the product of local operators associated with two or more independent graph tessellations. This model is versatile, encompasses several well-known discrete-time quantum walks, and inherits interesting features of the continuous-time quantum walk. We propose an implementation of the staggered quantum walk model with superconducting microwave resonators, where the required local operations are provided by the nearest neighbor interaction of the resonators coupled through superconducting quantum interference devices. The tunability of the interactions makes this system an excellent toolbox for this class of quantum walks. We focus on the one-dimensional case and discuss its generalization to a more general class known as triangle-free graphs CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP FUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJ Aberto

Agradecimentos: The authors would like to acknowledge Paulo Dainese for fruitful discussions and CCS-UNICAMP for providing the electron microscopy infrastructure Abstract: Optomechanical cavities have proven to be an exceptional tool to explore fundamental and applied aspects of the interaction between mechanical and optical waves. Here we demonstrate a novel optomechanical cavity based on a disk with a radial mechanical bandgap. This design confines light and mechanical waves through distinct physical mechanisms which allows for independent control of the mechanical and optical properties. Simulations foresee an optomechanical coupling rate g(0) reaching 2 pi x 100 kHz for mechanical frequencies around 5 GHz as well as anchor loss suppression of 60 dB. Our device design is not limited by unique material properties and could be easily adapted to allow for large optomechanical coupling and high mechanical quality factors with other promising materials. Finally, our devices were fabricated in a commercial silicon photonics facility, demonstrating g(0)/2 pi = 23 kHz for mechanical modes with frequencies around 2 GHz and mechanical Q-factors as high as 2300 at room temperature, also showing that our approach can be easily scalable and useful as a new platform for multimode optomechanics FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Aberto

Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (National Council for Scientific and Technological Development) (08/57857-2, 156468/2015-8); Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (Sao Paulo Research Foundation) (2012/17765-7, 2014/04748-2). The authors acknowledges Felipe Vallini and Felipe Santos for fruitful discussions and CCS-UNICAMP for providing the micro-fabrication infrastructure. Abstract: Coupled resonators are commonly used to achieve tailored spectral responses and allow novel functionalities in a broad range of applications. The Temporal Coupled-Mode Theory (TCMT) provides a simple and general tool that is widely used to model these devices. Relying on TCMT to model coupled resonators might however be misleading in some circumstances due to the lumped-element nature of the model. In this article, we report an important limitation of TCMT related to the prediction of dark states. Studying a coupled system composed of three microring resonators, we demonstrate that TCMT predicts the existence of a dark state that is in disagreement with experimental observations and with the more general results obtained with the Transfer Matrix Method (TMM) and the Finite-Difference Time-Domain (FDTD) simulations. We identify the limitation in the TCMT model to be related to the mechanism of excitation/decay of the supermodes and we propose a correction that effectively reconciles the model with expected results. Our discussion based on coupled microring resonators can be useful for other electromagnetic resonant systems due to the generality and far-reach of the TCMT formalism CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Aberto

Agradecimentos: We would like to thank Aaron C. Hryciw and J. P. Hadden for their assistance with this project. This work was supported by NRC, CFI, iCORE/AITF, NSERC, and CNPq Abstract: Resonant second harmonic generation between 1550 nm and 775 nm with normalized outside efficiency > 3.8 × 10 - 4 mW - 1 is demonstrated in a gallium phosphide microdisk supporting high-Q modes at visible (Q ~ 10 4) and infrared (Q ~ 10 5) wavelengths. The double resonance condition is satisfied for a specific pump power through intracavity photothermal temperature tuning using ~ 360 µ W of 1550 nm light input to a fiber taper and coupled to a microdisk resonance. Power dependent efficiency consistent with a simple model for thermal tuning of the double resonance condition is observed CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Agradecimentos: The authors acknowledge the staff of the NSF-NNCI’s San Diego Nanotechnology Infrastructure (SDNI) for their continued support in sample nanofabrication, modeling, and optical characterization. They also acknowledge Dr. Lin Pang, Brandon Hong, and Alexei Smolyaninov for helpful discussions. M. C. M. M. Souza acknowledges the São Paulo Research Foundation (2015/20525-6) Abstract: We experimentally investigate the application of magnetic fluids (MFs) on integrated silicon photonics. Using a ferro-fluid-clad silicon microring resonator, we demonstrate active control of resonances by applying an external magnetic field. Relatively high loaded quality factors on the order of 6000 are achieved, despite the optical losses introduced by the magnetic nanoparticles. We demonstrate resonance shifts of 185 pm in response to a 110 Oe strong magnetic field, corresponding to an overall refractive index change of -3.2 x 10(-3) for the cladding MF. The combination of MFs and integrated photonics could potentially lead to the development of magnetically controllable optical devices and ultra-compact cost-effective magnetic field sensors FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Aberto

Agradecimentos: We acknowledge FAPESP (2012/17610-3, 2012/17765-7 and 2013/06360-9) and CNPq (550504/2012-5) for financial support and CCS-UNICAMP for providing the micro-fabrication infrastructure Abstract: We demonstrate an optomechanical resonator that can tightly confine phonons through a circular phononic shield. Our design allows for independently trimmable long living optical and mechanical modes with large optomechanical coupling FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: Conselho Nacional de Desenvolvimento Científico e Tecnológico (National Council for Scientific and Technological Development) (08/57857-2), Fundação de Amparo à Pesquisa do Estado de São Paulo (São Paulo Research Foundation) (2012/17765-7, 2014/04748-2). The authors acknowledge T. P. M. Alegre for fruitful discussion and the Brazilian Nanotechnology National Laboratory (LNNano) during the fabrication process Abstract: Optical mode-splitting is an efficient tool to shape and fine-tune the spectral response of resonant nanophotonic devices. The active control of mode-splitting, however, is either small or accompanied by undesired resonance-shifts, often much larger than the resonance splitting. We report a control mechanism that enables reconfigurable and widely tunable mode splitting while efficiently mitigating undesired resonance shifts. This is achieved by actively controlling the excitation of counter-traveling modes in coupled resonators. The transition from a large splitting (80 GHz) to a single-notch resonance is demonstrated using low-power microheaters (35 mW). We show that the spurious resonance shift in our device is only limited by thermal crosstalk, and resonance-shift-free splitting control may be achieved CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Aberto

Agradecimentos: OPSN work is supported in part by CAPES. MCO acknowledges support by FAPESP and CNPq through the National Institute for Science and Technology on Quantum Information and the Research Center in Optics and Photonics (CePOF). GJM acknowledges the support of the Australian Research Council CE110001013. OPSN is grateful to L D Machado, S S Coutinho, K M S Garcez, J Lozada-Vera, A Carrillo and F Nicacio for helpful discussions Abstract: Measuring thermodynamic quantities can be easy or not, depending on the system that is being studied. For a macroscopic object, measuring temperatures can be as simple as measuring how much a column of mercury rises when in contact with the object. At the small scale of quantum electromechanical systems, such simple methods are not available and invariably detection processes disturb the system state. Here we propose a method for measuring the temperature on a suspended semiconductor membrane clamped at both ends. In this method, the membrane is mediating a capacitive coupling between two transmission line resonators (TLR). The first TLR has a strong dispersion, that is, its decaying rate is larger than its drive, and its role is to pump in a pulsed way the interaction between the membrane and the second TLR. By averaging the pulsed measurements of the quadrature of the second TLR we show how the temperature of the membrane can be determined. Moreover the statistical description of the state of the membrane, which is directly accessed in this approach is significantly improved by the addition of a Josephson junction coupled to the second TLR COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Agradecimentos: The authors would like to thank H. L. Fragnito and P. Dainese for loaning the equipments to perform part of the experiments. This work was supported by Brazilian financial agencies CNPq, CAPES, and the Center for Optics and Photonics (CePOF) under Grant 05/51689-2, the National Institute for Science and Technology (FOTONICOM) under Grant 08/57857-2, and Sao Paulo Research Foundation (FAPESP) Abstract: Single microring resonators have been used in applications such as wavelength multicasting and microwave photonics, but the dependence of the free spectral range with ring radius imposes a trade-off between the required GHz optical channel spacing, footprint and power consumption. We demonstrate four-channel all-optical wavelength multicasting using only 1 mW of control power, with converted channel spacing of 40-60 GHz. Our device is based on a compact embedded microring design fabricated on a scalable SOI platform. The coexistence of close resonance spacing and high finesse (205) in a compact footprint is possible due to enhanced quality factors (30,000) resulting from the embedded configuration and the coupling-strength dependence of resonance spacing, instead of ring size. In addition, we discuss the possibility of achieving continuously mode splitting from a single-notch resonance up to 40 GHz CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Aberto

Agradecimentos: D.S.F. thanks the financial support from Conselho Nacional de Desenvolvimento Cientifico e Tecnologico-CNPq (150232/2012-8), Brazil. We thank FAPESP and CNPq for financial support through the National Institute for Science and Technology of Quantum Information (INCT-IQ) and the Optics and Photonics Research Center (CePOF) Abstract: We present a novel approach for studying the dynamics of a superconducting qubit in a cavity. We succeed in linearizing the Hamiltonian through the application of an appropriate unitary transformation followed by a rotating wave approximation (RWA). For certain values of the parameters involved, we show that it is possible to obtain a Jaynes-Cummings type Hamiltonian. As an example, we show the existence of super-revivals for the qubit inversion FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Agradecimentos: This work was supported by the Sao Paulo Research Foundation (FAPESP) (project no. 2012/10476-0), by the National Council for Scientific and Technological Development (CNPq), by the Optics and Photonics Research Center (CePOF), and by the Brazilian National Institute for Science and Technology of Quantum Information (INCT-IQ) Abstract: In this work we investigate an optomechanical system consisting of two cavities coupled to the same mechanical resonator. We consider each cavity being weakly pumped as well as a small tunneling rate between the cavities. In such conditions, the system can be studied via quantum Langevin equations and the steady-state solution can be found perturbatively. In order to ensure that the approximations and methods used to study the system are suitable, the analytical results were compared to numerical results. We study the statistical properties of the cavity radiation fields and we show that depending on the values of the parameters of the system, it is possible to modify the spectrum of the cavities and enhance significantly the sub-Poissonian character of the cavity field FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Agradecimentos: We acknowledge Professor Paulo Nussenzveig for helpful discussions. This work was performed in part at the Cornell Nano-Scale Science and Technology Facility (a member of the National Nanofabrication Users Network), which was supported by NSF, its users, Cornell University, and Industrial users. The authors gratefully acknowledge support from DARPA for Award No. W911NF11 10202, supervised by Dr. Jamil AboShaeer. G. S. W. acknowledges FAPESP and CNPq INCT Fotonicom for financial support in Brazil Abstract: Optomechanical resonators suffer from the dissipation of mechanical energy through the necessary anchors enabling the suspension of the structure. Here, we show that such structural loss in an optomechanical oscillator can be almost completely eliminated through the destructive interference of elastic waves using dual-disk structures. We also present both analytical and numerical models that predict the observed interference of elastic waves. Our experimental data reveal unstressed silicon nitride (Si3N4) devices with mechanical Q-factors up to 104 at mechanical frequencies of f=102 MHz (fQ=1012) at room temperature FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Agradecimentos: We wish to thank O. P. de Sá Neto for his valuable participation at the beginning of this work and in the formulation of the problem. We would also like to thank Mauro Paternostro for his hints on multipartite entanglement analyzes. F.N. is grateful for financial support from FAPESP (Procs. 2009/16369-8). K.F. and F.L.S. acknowledge participation as members of the Brazilian National Institute of Science and Technology of Quantum Information (INCT/IQ). K.F. acknowledges partial support from CNPq under Grant No. 305568/2010-8. F.L.S. also acknowledges partial support from CNPq under Grant No. 308948/2011-4. F.N. and F.L.S. thank the Program "Science Without Borders" by CNPq Procs. 401265/2012-9 and Grant No. 150480/2013-0 Abstract: We study the entangling power of a nanoelectromechanical system (NEMS) simultaneously interacting with two separately trapped ions. To highlight this entangling capability, we consider a special regime where the ion-ion coupling does not generate entanglement in the system and any resulting entanglement will be the result of the NEMS acting as an entangling device. We study the dynamical behavior of the bipartite NEMS-induced ion-ion entanglement as well as the tripartite entanglement of the whole system (ions + NEMS). We found some quite remarkable phenomena in this hybrid system. For instance, the two trapped ions initially uncorrelated and prepared in coherent states can become entangled by interacting with a nanoelectromechanical resonator (also prepared in a coherent state) as soon as the ion-NEMS coupling achieves a certain value, and this can be controlled by external voltage gate on the NEMS device. We also show that, dynamically, the tripartite entanglement presents a more pronounced robustness against the destructive effects of dissipation when compared to the bipartite content FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2009 Este trabalho objetiva estudar sensores de temperatura sem fio baseados na tecnologia SAW (Surface Acoustic Wave - ondas acústicas superficiais). Os sensores SAW utilizados são baseados na sensibilidade dos parâmetros de propagação de ondas SAW em um substrato piezelétrico encapsulado em um circuito integrado. Estes sensores dispensam alimentação e podem ser interrogados à distância, sem fio. O conhecimento dos parâmetros do sensor é necessário para possibilitar o projeto de um interrogador para com ele formar um sistema de medição. Foi utilizado um único modelo de sensor, que opera na faixa de frequência de 433 MHz, com faixa de medição de (0 a 120) °C. Para a avaliação, foram utilizados equipamentos de radiofrequência ligados através de cabos e interface de conectores, exigindo o emprego de técnicas específicas para desacoplá-los, pois interferem significativamente no resultado das medições. Os critérios de avaliação do sensores se basearam nos diferentes indicadores de ressonadores e a comparação com sensores convencionais de temperatura. Chegou-se à conclusão de que a interface de comunicação entre equipamentos e dispositivo sob teste é muito relevante, alterando de forma significativa os resultados. Também concluiu-se que os sensores SAW tem resposta linear e comportamento estável com o tempo.

Agradecimentos: We acknowledge Paulo Nussenzveig, Richard Rand, and Steven Strogatz for fruitful discussion about our results. This work was supported in part by the National Science Foundation under Grant No. 0928552. The authors gratefully acknowledge the partial support from Cornell Center for Nanoscale Systems which is funded by the National Science Foundation and funding from IGERT (DEG-0654193). This work was performed in part at the Cornell NanoScale Science and Technology Facility (a member of the National Nanofabrication Users Network) which is supported by the National Science Foundation, its users, Cornell University, and Industrial users. G.S.W. acknowledges FAPESP and CNPq for financial support in Brazil Abstract: Synchronization, the emergence of spontaneous order in coupled systems, is of fundamental importance in both physical and biological systems. We demonstrate the synchronization of two dissimilar silicon nitride micromechanical oscillators, that are spaced apart by a few hundred nanometers and are coupled through an optical cavity radiation field. The tunability of the optical coupling between the oscillators enables one to externally control the dynamics and switch between coupled and individual oscillation states. These results pave a path toward reconfigurable synchronized oscillator networks FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Agradecimentos: The authors would like to thank the financial agencies Fundação de Amparo à Pesquisa no Estado de São Paulo (FAPESP), Conselho Nacional de Pesquisa (CNPq), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and to the Centro de Componentes Semicondutores (CCS). This work was performed under the Instituto Nacional de Ciência e Tecnologia FOTONICOM Abstract: A study of damages caused by gallium focused ion beam (FIB) into III-V compounds is presented. Potential damages caused by local heating, ion implantation, and selective sputtering are presented. Preliminary analyzes shows that local heating is negligible. Gallium implantation is shown to occur over areas tens of nanometers thick. Gallium accumulation as well as selective sputtering during III-V compounds milling is expected. Particularly, for GaAs, this effect leads to gallium segregation and formation of metallic clusters. Microdisks resonators are fabricated using FIB milling with different emission currents to analyze these effects on a device. It is shown that for higher emission current, thus higher implantation doses, the cavity quality factor rapidly decreases due optical scattering losses induced by implanted gallium atoms FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: The authors thank CAPES, CNPq, FAPESP, FOTONICOM, CePOF and the National Science Foundation through NSF ERC Center for Integrated Access Networks (Grant EEC-0812072) and Cornell NanoScale Facility, a member of the National Nanotechnology Infrastructure Network, which is supported by the (Grant ECS-0335765), for financial support. The authors also thank the Electronic Warfare Laboratory at ITA, Photonics Division at IEAv, and the Kavli Nanoscience Institute at Caltech, for the technical support Abstract: A proof-of-concept for a new and entirely CMOS compatible thermo-optic reconfigurable switch based on a coupled ring resonator structure is experimentally demonstrated in this paper. Preliminary results show that a single optical device is capable of combining several functionalities, such as tunable filtering, non-blocking switching and reconfigurability, in a single device with compact footprint (similar to 50 mu m x 30 mu m) COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Aberto

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2011 Máquinas oscilantes são encontradas em diversas aplicações na engenharia, tais como motores de combustão interna, compressores, motogeradores, moto vibradores, e diversos outros equipamentos. Muitas destas máquinas, ao realizar a função a que se destinam, acabam por irradiar altos níveis de potência sonora. Em aplicações como compressores para refrigeração este ruído irradiado é muito prejudicial ao consumidor final. Isso motiva as indústrias a buscarem o desenvolvimento de produtos cada vez mais com um maior conforto acústico. Neste trabalho é mostrado um estudo realizado em um compressor para refrigeração que tem um padrão de radiação tonal bem característico e similar a um dipolo. O objetivo do trabalho foi analisar a aplicação de três conceitos de atenuação de ruído bem conhecidos na área de acústica e vibrações. O primeiro envolve o uso de um absorvedor dinâmico de vibrações, com o intuito de reduzir a vibração do compressor e com isso reduzir o ruído radiado. Outras tecnicas também avaliadas baseiam-se na redução da efciência de radiação das paredes radiadoras através da adição de absorvedores acústicos como um painel de membrana e ressonadores de Helmholtz. Para isso, inicialmente foi feito um trabalho de caracterização do padrão de radiação utilizando a técnica experimental de holografia acústica, teorias de monopolos e dipolos, e as técnicas de elementos de contorno e elementos finitos acústicos. Estas duas últimas foram então utilizadas para avaliar e projetar as soluções propostas, que foram então prototipadas e avaliadas experimentalmente para confirmar os efeitos previstos numericamente.

Orientador: Newton Cesário Frateschi Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin Resumo: Este trabalho apresenta o uso de cavidades ressonantes baseadas em geometrias de bilhares caóticos construídas em meios semicondutores opticamente ativos, visando seu aproveitamento ao sensoriamento. Apesar do comportamento clássico caótico do estádio, a descrição quântica, no limite semiclássico, mostra inesperados acúmulos de densidade de probabilidade sobre muitas trajetórias periódicas fechadas, chamadas cicatrizes. A literatura mostra que o espaço físico das trajetórias relacionadas a cada cicatriz pode ser obtido pela soma da densidade de probabilidade de auto-estados na vizinhança de cada cicatriz. Classicamente, as trajetórias ligadas a cada auto-estado possuem órbitas muito próximas devido a sua instabilidade, e quando misturadas, definem uma órbita de largura não nula. No domínio óptico, isomórfico ao problema quântico descrito acima, as trajetórias vêm de um tratamento de traçado de raios e os auto-estados são os modos eletromagnéticos estacionários. Particularmente, no caso da cavidade dielétrica, o sistema é aberto, uma vez que a luz pode ser transmitida para fora do ressonador. Desta forma, há grande mistura dos modos e uma seleção maior daqueles que podem sobreviver por terem trajetórias com ângulos internos de incidência maiores que o ângulo crítico para reflexão total interna. Em uma trajetória fechada e curta, modos estacionários são definidos e essas trajetórias têm maior probabilidade de serem observadas, em relação a outras possíveis. Quando o ressonador é constituído por um meio ativo opticamente, este confinamento realiza a realimentação óptica do sistema, cujo ganho óptico permite o estabelecimento estável e coerente de tais trajetórias. Estes resultados inspiraram a realização deste trabalho, cuja grande motivação foi investigar o processo de seleção modal e aplicá-lo em dispositivos práticos para sensoriamento em pequenos volumes. Experimentalmente foi desenvolvida uma técnica híbrida de fabricação utilizando um sistema de íons focalizados (FIB) juntamente com técnicas de microfabricação convencionais para a produção de cavidades estádio com meio ativo de poços quânticos de InGaAsP. Finalmente, foram obtidos resultados da emissão espectral com grande concordância com a previsão teórica baseada numa abordagem matemática simples de soma incoerente de cicatrizes. A seleção modal foi demonstrada com a alteração da excentricidade e com a inserção de furos sobre as trajetórias. A aplicação ao sensoriamento foi explorada tanto pela observação do espectro de emissão quanto pela detecção de fotocorrente por estádios emissor e detector integrados. Variações de até 80% de fotocorrente e alterações significativas do espectro foram observadas para detecção de isopropanol e água. Estes resultados mostram possibilidades de sensoriamento prático utilizando os estádios Abstract: This work presents the development of resonant cavities based on chaotic billiard geometries built with semiconductor active optical medium for sensing applications. In spite of the classically chaotic behavior of the stadium, the quantum description of the problem in the semi-classical limit shows unexpected accumulations of the density of probability on closed periodic paths called scars. The literature shows that the physical space of the paths related to a given scar can be obtained by adding several eigen-states neighboring each scar. Classically, the paths connected to each eigen-state have very close orbits due to their instability which, when mixed, define a non-zero width orbit. In the optical domain, isomorphic to the quantum problem described above, the paths are a result of the ray treatment and the eigen-modes are the stationary electromagnetic modes. Particularly, in the case of a dielectric cavity, the system is open for light can escape the resonator. Therefore, there is a great mixture of modes and a strong selection of modes with paths with incidence angle below the critical angle. In a closed and short path, stationary modes are defined and those paths have larger probability of observation. When the resonator has an optically active medium, the confinement provides optical feedback to the system which with optical gain allows the establishment of coherent and stable scars. These results inspired this work where the process of modal selection was investigated and applied for sensing in small volumes. Experimentally, a hybrid fabrication approach based on Focused Ion Beam (FIB) and conventional micro-fabrication techniques was used to produce stadium optical cavities with InGaAsP quantum well active region. Finally, we obtained the spectral emission of the devices with good agreement with our simulation based on a simple mathematical approach employing the incoherent summation of the scars. The modal selection with the modification of the eccentricity of the cavity and with the insertion of holes along the scars was demonstrated. The application to sensing was explored by the observation of the emission spectrum as well as by measured photo-current on detection between stadia emitter and detector integrated. Photo-current variations of up to 80% and significant changes of the emission spectrum were observed for isopropanol and water detection. These results show possibilities of practical sensing by stadiums Doutorado Física Doutor em Ciências

Agradecimentos: The authors thank Luis E. E. de Araujo for discussions. LSC and MS acknowledge scholarships from FAPESP, FCC (flavio@ifi.unicamp.br) acknowledges financial support from FAPESP, CEPOF, CNPq, and AFOSR Abstract: We describe a setup for a deep optical dipole trap or lattice designed for holding atoms at temperatures of a few mK, such as alkaline-Earth atoms which have undergone only regular Doppler cooling. We use an external optical cavity to amplify 3.2 W from a commercial single-frequency laser at 532 nm to 523 W. Powers of a few kW, attainable with low-loss optics or higher input powers, allow larger trap volumes for improved atom transfer from magneto-optical traps. We analyze possibilities for cooling inside the deep trap, the induced Stark shifts for calcium, and a cancellation scheme for the intercombination clock transition using an auxiliary laser FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto