Atualmente, os materiais luminescentes que apresentam a luminescência persistente tem ganhando um destaque devido a capacidade de emitir luz por um período de tempo que pode variar de minutos à horas depois de cessada a excitação. Todavia, não há um grande número de estudos quantitativos a respeito dos fatores que influenciam esse fenômeno. Dessa forma, para o estudar do efeito do band gap na luminescência persistente comparou-se as propriedades de duas matrizes similares. A matriz ortossilicato de cádmio, Cd2SiO4, foi comparada com a matriz metassilicato de cádmio, CdSiO3, já descrita na literatura. A matriz ortossilicato de cádmio não dopada e dopada com íons terra rara foi sintetizada via síntese de estado sólido pelo método cerâmico a 1050 °C. A caracterização e o estudo da pureza se deram através das técnicas difração de raios X (DRX) usando radiação Síncrotron e CuKα. O estado de oxidação foi estudado usando espectroscopia de absorção de raios X próximo a borda (XANES) com radiação Síncrotron. As propriedades luminescentes foram compreendidas pelos experimentos de fotoluminescência no UV-Vis e espectroscopia com radiação Síncrotron na região do UV vácuo. Os difratogramas mostraram a presença de pequenas porcentagens de impurezas e a obtenção da fase pura para o Cd2SiO4:Pr3+. O espectro de XANES mostrou a presença apenas de íons terras raras trivalentes. O valor do band gap para a matriz ortossilicato de cádmio em 4,1 eV foi determinado utilizando espectros de excitação e emissão em 77 K dos materiais Cd2SiO4 e Cd2SiO4:Gd3+. Os espectros de excitação e emissão dos materiais Cd2SiO4:Pr3+ e Cd2SiO4:Tb3+ permitiram a comparação das propriedades luminescentes entre a fase ortossilicato e metassilicato, além de indicar a posição de alguns níveis 5d dentro da banda de condução. Com os dados obtidos foi proposto um mecanismo de luminescência persistente para o íon Pr3+ que mostrou-se muito mais eficiente nessa matriz em relação ao metassilicato de cádmio, comportamento oposto ao observado com os íons Tb3+, devido às suas posições dentro do band gap da matriz / Persistent luminescence materials have gained special attention lately due to their special property of emitting light for long time after ceased irradiation. However, hitherto, there is no deep quantitative analysis on the factors that affects this phenomenon. On this way, we compared the persistent luminescence properties on two similar inorganic hosts differing only in their band gap energies. The cadmium orthosilicate (Cd2SiO4) was compared to the cadmium metasilicate (CdSiO3) already well described in literature. The non-doped and rare earth doped cadmium orthosilicate were prepared with solid state synthesis at 1050 °C. The characterization and phase purity study were made with X-ray diffraction techniques using both Synchrotron and CuαK radiation. The oxidation state was studied with Synchrotron radiation X-ray absorption Near Edge structure measurements (XANES). The photoluminescence study was done with UV-Vis and VUV-UV emission and excitation spectroscopies. The XRD patterns allowed the determination of the phase purity and confirmed the preparation of pure Cd2SiO4:Pr3+. XANES data confirmed the presence of only trivalent rare earths. The band gap was determined as 4.1 eV with the 77 K excitation spectra of Cd2SiO4 and Cd2SiO4:Gd3+. The excitation spectra of Cd2SiO4:Pr3+ and Cd2SiO4:Tb3+ allowed the comparation between the optical properties of meta- and orthosilicate crystal phases like the position of 5d levels which are inside Cd2SiO4 conduction band. The obtained data allowed the proposition of a persistent luminescence mechanism for Pr3+ ion, considerably more efficient on orthosilicate when compared to metasilicate. This behavior is on the opposite way to the one observed for Tb3+ ions, due to their position in the band gap.

Made available in DSpace on 2017-07-21T19:25:46Z (GMT). No. of bitstreams: 1 Rubyan Lucas Santos Piazzetta.pdf: 4250981 bytes, checksum: c1d20c3e7f1d1d4307bef8d9dee045f7 (MD5) Previous issue date: 2015-03-23 / Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná / This work studied tellurite glasses in a ternary system with the TeO2-Li2O-ZnO composition, divided in three groups with 10%, 15% and 20%mol Li2O fixed. For this study, was made the replacement of known TeO2 network former by ZnO. It used the Differential Scanning Calorimetry (DSC), optical absorption in ultraviolet-visible region (UV-VIS), Raman spectroscopy, Fourier transform infrared (FTIR), linear refractive index (n0) measurement and instrumented nanoindentation. The samples were prepared by melt quenching method in the bulk form. DSC results showed that the glass transition temperature (TG) virtually no change in the glass systems, while that there was an increase in the glass stability due to exchange of TeO2 by ZnO especially for 10 and 15% mol Li2O groups. By continuing, the UV-VIS results indicated a gradual increase in the band gap energy which was calculated by Urbach rule; this increased energy as TeO2 was replaced by ZnO, can also be seen as a blue shift. These same results were confirmed by a structural change seen by Raman spectroscopy: with the increased of ZnO, the vibrational modes located at 450 e 659 cm-1 which incorporate trigonal bipyramids of TeO4 are gradually replaced by vibrational modes at 735-760 cm-1 referred the creation of Zn2Te3O8 units. This behavior by Raman spectroscopy is also confirmed by the FTIR results with increased intensity of peaks related to vibrational modes of ZnO molecules. Therefore, it is verified that the addition of ZnO in the system has the property to decrease the amount of NBOs, which in turn decreases the polarizability of the oxide ion of the system and increases the band gap energy. Lastly, the increase in the band gap values and, Raman and DSC results showed that this glassy system acquires considerable glass stability, has good transmittance in the ultraviolet and visible regions, and thus appears as a promising candidate for host ions optically active. / Esta dissertação teve por objetivo estudar os vidros teluretos em um sistema ternário com composição TeO2-Li2O-ZnO, separados em três grupos com concentração fixa de 10%, 15% e 20% em mol de Li2O com a respectiva substituição do conhecido formador de rede TeO2 por ZnO. Tal estudo agregou as técnicas de Calorimetria Diferencial de Varredura (DSC), absorção óptica na região do ultravioleta-visível (UV-VIS), espectroscopia Raman, infravermelho por transformada de Fourier (FTIR), medidas de índice de refração linear (n0) e nanoindentação instrumentada. As amostras foram preparadas pelo método de melt quenching e obtidas na forma de bulk. Por meio dos resultados de DSC verificou-se que a temperatura de transição vítrea (TG) fica praticamente inalterada nesse sistema vítreo, enquanto que existe um aumento expressivo da estabilidade vítrea com a troca de TeO2 por ZnO, principalmente para os grupos com 10 e 15% em mol de Li2O. Já os resultados de UV-VIS mostraram um aumento gradual na energia de band gap, a qual foi calculada utilizando a Regra de Urbach. Esse aumento de energia, à medida que TeO2 era substituído por ZnO, também pode ser visto como um blue shift (deslocamento para o azul). Esse aumento de band gap foi confirmado por uma mudança estrutural vista por espectroscopia Raman: com o aumento na concentração de ZnO, os modos vibracionais localizados em 450 e 659 cm-1 que incorporam bipirâmides trigonais de TeO4 passam a ser gradualmente substituídos por modos vibracionais em 735-760 cm-1 que se referem a criação de unidades Zn2Te3O8. Esse comportamento por espectroscopia Raman também é confirmado através dos resultados de FTIR com aumento da intensidade dos picos relacionados a modos vibracionais de moléculas ZnO. É verificado assim que a adição de ZnO ao sistema tem a propriedade de diminuir a quantidade de NBOs, o que por sua vez, diminui a polarizabilidade do íon óxido do sistema e aumenta a energia de band gap. Com isto, o aumento nos valores de band gap e os resultados de DSC e Raman mostraram que esse sistema vítreo adquire considerável estabilidade vítrea, tem boa transmitância nas regiões do ultravioleta e visível e, assim, se mostra como um promissor candidato para hospedeiro de íons opticamente ativos.

Nesse trabalho foram fabricados filmes finos de TiO2 por RF magnetron sputtering reativo sobre substrato de silício (1 0 0). A pressão parcial do oxigênio na câmara foi variada de 5 a 100% em relação ao argônio. Após a deposição os filmes foram submetidos a tratamento térmico em atmosfera de oxigênio. A estequiometria dos filmes e o perfil de profundidade foram obtidos por RBS. A estrutura cristalina foi obtida por XRD. As propriedades ópticas foram obtidas por interferometria e reflectância e as elétricas por meio das curvas C-V. Os valores de espessura dos filmes sem tratamento térmico aumentaram aproximadamente 41% com o aumento do oxigênio na câmara de deposição. Essa variação está ligada ao aumento da eficiência do sputtering do alvo. Os índices de refração dos filmes sem tratamento térmico se mantiveram dentro de um intervalo de aproximadamente 2,3 a 2,4. A diminuição do band gap com o tratamento térmico é consequência da mudança de fase cristalográfica de anatase para rutila. A estequiometria TiOx dos filmes antes do tratamento térmico apresentaram valores de x entre 2,0 e 2,4. A espessura em TFU dos filmes aumentou com o percentual de oxigênio na câmara. As amostras que receberam tratamento térmico apresentaram difusão de titânio na interface do substrato e incorporação de oxigênio no filme. Os valores da constante dielétrica aumentaram com o percentual de oxigênio na câmara, em contraposição com o efeito do tratamento térmico que diminuiu o valor. Todos os resultados observados são coerentes do ponto de vista da mudança de fase anatase rutila e aumento do percentual de oxigênio na câmara. / In this work thin films of TiO2 were produced by reactive RF magnetron sputtering on silicon substrate (1 0 0). The oxygen partial pressure in the chamber was varied from 5 to 100% in relation to argon. After deposition the films were submitted to thermal treatment under an oxygen atmosphere. The stoichiometry of the films and the depth profile were obtained by RBS. The crystal structure was obtained by XRD. Its optical properties were obtained by interferometry and reflectance and the electrical were obtained by means of the C-V curves. The thickness values of films without heat treatment increased approximately 41% with the increase of oxygen in the deposition chamber. This variation is linked to the increased sputtering efficiency of the target. The refractive indexes of films without heat treatment remained within a range of about 2.3 to 2.4. The decrease of the band gap with the heat treatment is a consequence of the change of crystallographic phase from anatase to rutile. The TiOx stoichiometry of the films before the heat treatment showed values of x between 2.0 and 2.4. The TFU thickness of the films increased with the percentage of oxygen in the chamber. The samples that received heat treatment shows diffusion of titanium at the interface of the substrate and incorporation of oxygen in the film. The values of the dielectric constant increased with the percentage of oxygen in the chamber, as opposed to the effect of the thermal treatment that decreased the value. All the results observed are consistent from the point of view of the anatase - rutile phase transition and the increase in the oxygen percentage in the chamber.

Made available in DSpace on 2017-07-21T19:25:46Z (GMT). No. of bitstreams: 1 Joao Luiz Gomes Junior.pdf: 5004861 bytes, checksum: 0e45ece35c737cce76186e1babb5e257 (MD5) Previous issue date: 2015-03-26 / Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná / In this work, the correlation between the structural morphology with thermal, optical and mechanical properties of (1 – x – y)TeO2-xLi2O-yMoO3 glasses was studied. The analysis was divided into three sets of samples, varying according to the composition for technique. The results reveal different behaviors for each set vitreous stabilities. The Raman spectroscopy and FTIR results showed a similar structural change between each set with decrease NBOs and new peaks position. The Raman and FTIR spectra results showed that with increasing content x and y, concomitantly, occur the conversion of TeO4 to TeO3+1 units, then, in addition to TeO3 units. Furthermore occurs change coordination in the structural units Mo atoms 4 to 6 and these structural changes. Li addition causes these structural changes. This fact confirmed by the Band Gap energy values, which increase with the increase of x and y, it decreases the optical basicity and refractive index values. By optical absorption measurements determined the Band Gap energy values of all samples. It was concluded that occur direct transitions allowed in all sets. The behavior of increasing Band Gap values and decreasing Optical basicity confirmed the decreasing in the NBO content leading to an indication of a more polymerized network for a variation of x mol%. Finally the behaviors elastic modulus and hardness, which shows decreased stiffness of the material with the incorporation of Li2O and MoO3 concomitantly, is presented. x / Este trabalho apresenta as correlações entre a morfologia estrutural e as propriedades térmicas, ópticas e mecânicas nos vidros (1 – x – y)TeO2 – xLi2O – yMoO3. Dividiram-se as análises em três conjuntos de amostras, de acordo com variação da composição, para cada técnica utilizada. Os resultados revelam diferentes comportamentos de estabilidades vítreas para cada conjunto. As medidas por espectroscopia de Raman e FTIR mostram mudanças estruturais similares entre cada conjunto com diminuição dos NBOs e novas posições de picos. Os resultados de Raman e FTIR mostram que com o aumento em conteúdo x e y ocorre a transformação de unidades TeO4 para TeO3 + 1 e, em seguida, para TeO3 além disso ocorre a mudança de coordenação do átomo de Mo de 4 para 6 e estas alterações estruturais têm sido relacionados com a adição de átomos de Li. Este fato é confirmado pelos valores de energia de Band Gap, que aumentam com o incremento de x e y, e diminuição dos valores de basicidade óptica e índice de refração. As energias de Band Gap, para todas as amostras, foram determinadas por medidas de absorção óptica na região do Ultravioleta. Foi concluído que ocorrem transições diretas permitidas em todos os conjuntos. E por fim apresenta-se os comportamentos de dureza e Módulo elástico, o que revela diminuição da rigidez do material com a incorporação de Li2O e MoO3 concomitantemente.

Made available in DSpace on 2017-07-21T19:25:51Z (GMT). No. of bitstreams: 1 Anderson Goncalves.pdf: 4030302 bytes, checksum: 6c04b9e37c0aaf5b0f1e9c3ecb66a216 (MD5) Previous issue date: 2016-02-22 / Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná / In this work were studied the tellurite glasses of the glass system (100-x-y)TeO2-yLi2O-xBaO obtained by melt quenching method and characterized by techniques X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Raman Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), UV-Vis Spectroscopy, linear refractive index and density measurements. The results of DRX measurements allowed classifying the samples with a standard characteristic diffraction amorphous structures. The DSC results show that the samples located close to the center of the glass-forming region have the highest values for the thermal stability, these being greater than 100 °C. Results of Raman spectroscopy show that there is a decrease in the connectivity of the network glass formed and of the TeO4 units with decreasing amount of tellurium. The units of TeO3+1 show an increase while for TeO3 units there is not a well defined behavior. The FTIR results show a decrease in TeO4 units and increase in TeO3 units with decreasing amount of tellurium. The Band Gap (Eg) energy values obtained are in agreement with those found in the literature for tellurite glasses. The results also indicate that electronic transitions that occur are of the type permitted indirect, still being observed an increase in Eg values as tellurium replaced. The structural changes create Non Bridging Oxygen (NBO), but the connection between the NBO and Te atoms is weak, which do not influence in Eg behavior. This influence starts to be strong above a certain value of BaO content (which depends on the Li2O content). While these values to the energy band gap increase, the values of the linear refractive index decreases, agreeing with what is presented in the literature. For polarizability ion oxide, only the samples with 5% Li2O shows behavior consistent with what is reported in the literature, inversely proportional to the Band Gap values and proportional to the refractive index. / Neste trabalho foram estudados os vidros teluretos do sistema vítreo (100-x-y)TeO2-yLi2O-xBaO obtidos pelo método de melt quenching e caracterizados pelas técnicas de Difração de Raios X (DRX), Calorimetria Diferencial de Varredura (DSC), Espectroscopia Raman, Espectroscopia no Infravermelho por Transformada de Fourier (FTIR), Espectroscopia UV-Vis, medidas de índice de refração linear e densidade. Os resultados das medidas de DRX permitiram classificar as amostras que apresentavam um padrão de difração característico de estruturas amorfas. Os resultados de DSC mostraram que as amostras localizadas próximas ao centro da região de formação vítrea apresentaram os maiores valores para a estabilidade térmica, sendo estes maiores que 100 °C. Os resultados de espectroscopia Raman mostraram que ocorre uma diminuição na conectividade da rede vítrea formada e das unidades de TeO4 com a diminuição da quantidade de telúrio. As unidades de TeO3+1 apresentaram um aumento, enquanto que para as unidades de TeO3 não há um comportamento bem definido. Os resultados de FTIR mostraram uma diminuição nas unidades de TeO4 e um aumento nas unidades de TeO3 com a diminuição da quantidade de telúrio. Os valores de energia de Band Gap (Eg) obtidos estão de acordo com os encontrados na literatura para vidros teluretos. Os resultados também indicam que as transições eletrônicas que ocorrem são do tipo permitida indireta, sendo observado ainda um aumento nos valores de Eg à medida que o telúrio é substituído. As modificações estruturais que ocorreram criam oxigênios não ligados (NBO – non-bridging-oxygen), mas os mesmos são fracamente conectados aos átomos de Te, não influenciando tanto nos valores de Eg até certa quantidade de BaO (que depende da quantidade de Li2O). Enquanto estes valores para a energia de Band Gap aumentam, os valores para o índice de refração linear diminuem, concordando com o que é apresentado pela literatura. Para a polarizabilidade do íon óxido, apenas as amostras com 5% de Li2O apresentaram comportamento coerente com o que é reportado na literatura, sendo inversamente proporcional ao Band Gap e proporcional ao índice de refração.

Ce travail de recherche prédictive, couplé à des synthèses expérimentales, a pour but d'anticiper la bonne adéquation entre un nouveau polymère donneur de type P3HT et un composé accepteur innovant à base de graphène. Cette étude a notamment porté sur i) la bande d'absorption du polymère donneur « low band gap », ii) sa robustesse face à la dégradation (cristallinité, résistance à l'oxydation), iii) la modulation des propriétés électroniques d'un dérivé de graphène (accepteur) en adéquation avec le donneur. Les résultats montrent que les polythiophènes ayant un substituant éther OR permettent l'amélioration de la conjugaison, de la rigidité, de la cristallinité et de la photostabilité tout en étant électroniquement compatible avec l'hexabenzocoronène fonctionnalisé (acide caorboxylique). De plus, ce nouvel accepteur sera pleinement compatible avec une électrode de graphite grâce à sa prédisposition à l'empilement colonnaire. / This predictive research work, combined with an experimental study, aims at anticipate the behavior of a new donor :acceptor pair constituted by a P3HT-type of polymer and an innovative graphene-based acceptor material (HBC). This study is particularly interested in i) the absorption band of the donor (a « low band gap » polymer) and ii) its resistance towards degradation (cristallinity, oxidation stability), and finally iii) the modulation of the electronic properties of the acceptor, in keeping with those of the donor. Results show that polythiophenes grafted with an –OR group improve both conjugation, rigidity, cristallinity and photostability, in addition to their great electronic compatibility with functionalized HBCs. Besides, this new acceptor material will be fully compatible with a graphite electrode, thanks to its columnar structuration.

A large variety of material systems for light emission and detection were studied: from very small band gap semiconductors for infra-red (IR) detectors to wide band gap semiconductors for ultra violet (UV) emission as well as CdSe/ZnSe QDs for single photon emitters and rare earth doped oxides for laser fabrication. The growth and characterization aspects were tackled. This work will focus on the relations between the growth procedures and the optical properties. The information that can be gained from optical studies as well as the limitations of those ones will be explained in each case. Following that, a number of projects will be presented. The main one will be based on how to circumvent the problems linked with p-type doping of wide bandgap semiconductors. This project, based on field effect hole injection in wide band-gap semiconductors addresses the major challenge of fabricating efficient deep UV emitters.

Because of their outstanding characteristics, micro/nano-mechanical (MM) structures have found a plethora of applications in wireless communications and sensing. Many of these MM structures utilize mechanical vibrations (or phonons) at megahertz or gigahertz frequencies for their operation. On the other hand, the periodic atomic structure of crystals is the fundamental phenomenon behind the new era of electronics technology. Such atomic arrangements lead to a periodic electric potential that modifies the propagation of electrons in the crystals. In some crystals, e.g. silicon (Si), this modification leads to an electronic band gap (EBG), which is a range of energies electrons can not propagate with. Discovering EBGs has made a revolution in the electronics and through that, other fields of technology and the society. Inspired by these trends of science and technology, I have designed and developed integrated MM periodic structures that support large phononic band gaps (PnBGs), which are ranges of frequencies that phonons (and elastic waves) are not allowed to propagate. Although PnBGs may be found in natural crystals due to their periodic atomic structures, such PnBGs occur at extra high frequencies (i.e., terahertz range) and cannot be easily engineered with the current state of technology. Contrarily, the structures I have developed in this research are made on planar substrates using lithography and plasma etching, and can be deliberately engineered for the required applications. Although the results and concepts developed in this research can be applied to other substrates, I have chosen silicon (Si) as the substrate of choice for implementing the PnBG structure due to its unique properties. I have also designed and implemented the fundamental building blocks of MM systems (e.g., resonators and waveguides) based on the developed PnBG structures and have shown that low loss and efficient MM devices can be made using the PnBG structures. As an example of the possible applications of these PnBG structures, I have shown that an important source of loss, the support loss, can be suppressed in MM resonators using PnBG structures. I have also made improvements in the characteristics of the developed MM PnBG resonators by developing and employing PnBG waveguides. I have further shown theoretically, that photonic band gaps (PtBGs) can also be simultaneously obtained in the developed PnBGs structures. This can lead to improved photon-phonon interactions due to the effective confinement of optical and mechanical vibrations in such structures. For the design, fabrication, and characterization of the structures, I have developed and utilized complex and efficient simulation tools, including a finite difference time domain (FDTD), a plane wave expansion (PWE), and a finite elements (FE) tool, each of which I have developed either completely from scratch, or by modification of an existing tool to suit my applications. I have also developed and used advanced micro-fabrication recipes, and characterization methods for realizing and characterizing these PnBG structures and devices. It is agued that by using the same ideas these structures can be fabricated at nanometer scales to operate at ultra high frequency ranges. I believe my contributions has opened a broad venue for new MM structures based on PnBG structures with superior characteristics compared to the conventional devices.

Made available in DSpace on 2014-12-17T14:55:47Z (GMT). No. of bitstreams: 1 DaviBB.pdf: 1037005 bytes, checksum: 218c25a038f89588a46ddca7509b0705 (MD5) Previous issue date: 2006-07-06 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The aim of this work is to characterize and use the characteristic parameters of the planar structures constructed with fin lines looking for their applications in devices, using PBG Photonic Band Gap photonic materials as substrate, operating in the millimeter and optic wave bands.The PBG theory will be applied for the relative permittivity attainment for the PBG photonic substrate s and p polarizations. The parameters considered in the structures characterization are the complex propagation constant and the characteristic impedance of unilateral and bilateral fin lines that were obtained by the use of the TTL Transverse Transmission Line Method, together with the Method of the Moments. The final part of this work comprises studies related to the behavior of the asymmetric unilateral fin line coupler with photonic substrate. This research opens perspectives for new works in this modern area. Numerical results are shown by means of bi-dimensional and three-dimensional graphics. Conclusions and suggestions for future works are also presented / O presente trabalho tem como objetivo caracterizar e utilizar os par?metros de estruturas planares constru?das com linhas de l?minas visando a sua utiliza??o em circuitos, com materiais fot?nicos do tipo PBG Photonic Band Gap como substrato, operando nas faixas de ondas milim?tricas e ?pticas. A teoria PBG ser? aplicada para a obten??o da permissividade relativa para as polariza??es s e p dos substratos compostos de material fot?nico PBG. Os par?metros considerados na caracteriza??o das estruturas s?o a constante de propaga??o complexa e a imped?ncia caracter?stica, de linhas de l?mina unilaterais e bilaterais, que foram obtidos atrav?s da utiliza??o do m?todo da Linha de Transmiss?o Transversa LTT com o aux?lio do M?todo dos Momentos. Nesse trabalho foi realizado ainda, um estudo do funcionamento do acoplador com linha de l?mina unilateral assim?trica com substrato fot?nico. Esta pesquisa abre perspectivas para novos trabalhos nesta moderna ?rea. A an?lise te?rica computacional desse trabalho se mostrou precisa, com compara??es de outros trabalhos, podendo ser empregada em outros dispositivos que utilizem a linha de l?mina como estrutura b?sica, e materiais ?pticos. Resultados num?rico-computacionais em forma de gr?fico em duas e tr?s dimens?es para todas as an?lises realizadas s?o apresentados, para as estruturas propostas que tem como substratos materiais fot?nicos. S?o apresentadas conclus?es e sugest?es para a continuidade deste trabalho

Master of Science / Department of Physics / Kristan L. Corwin / We investigate the nonlinear spectroscopy of acetylene in the near infrared region inside a photonic band gap fiber. The near infrared region of the optical spectrum is an area of intensive research due to its relevance to telecommunication and optical metrology. Acetylene provides a large number of reference transitions coincident with the international telecommunication band. Acetylene contains about 50 strong lines between 1510 nm and 1540 nm in the ν1+ν3 ro-vibrational combination band. We have observed the Doppler-free saturated spectrum of several of these lines. The light from a tunable diode laser at ~1531 nm, resonant with the P(11) transition, is amplified by an erbium doped fiber amplifier and split into a strong pump beam and weak probe beam which counter-propagate inside the gas-filled fiber. The measured Doppler linewidth of the P(11) line at room temperature is about 467 MHz wide. The sub-Doppler profile over a pressure range of 200-1600 mT appears as a narrow absorption feature about 20-40 MHz wide, even at the low pump power of ~10 mW. It is found that for a fiber with an 80 cm length, 20 core size, pumped with 29 mw, the optimum pressure is ~530mT. But the optimum pressure condition will further decrease when the fiber length increases.