Nonlinear Refraction
Mostrando 1-12 de 16 artigos, teses e dissertações.
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1. The influence of ethoxylation degree in the behaviour of secondary alcohol ethoxylates / Influência do grau de etoxilação no comportamento de álcoois secunários etoxilados
The solubilization of non-ionic solutes via partitioning between water and the micellar pseudophase of non-ionic surfactants was evaluated for a series of secondary alcohol ethoxylates with hydrophile length varying from 7 to 40 ethylene oxide units. It was demonstrated that the micellar incorporation constant, Ks, is not dependent on the hydrophile length o
Publicado em: 2009
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2. Espectroscopia Ãptica nÃo linear de vidros especiais e colÃides
Nonlinear optical properties of special glasses and colloids were studied using the zscan technique. This technique aalows to calculate the nonlinear refraction index and the nonlinear absorption coefficient using the self-focusing or defocusing effect that appears when the incident laser pass through a nonlinear medium. Orthophosphate and polyphosphate anti
Publicado em: 2008
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3. SÃntese e caracterizaÃÃo de nanopartÃculas de nÃquel para Ãptica nÃo linear / SÃntese e caracterizaÃÃo de nanopartÃculas de nÃquel para Ãptica nÃo linear
In this work, we describe the synthesis of nickel nanoparticles (NPs) stabilized using poly (vinyl pyrrolidone), their structural and optical (linear and nonlinear) characterization. In Chapter 1 we present a general introduction describing the work performed. In Chapter 2 it is presented a review of nickel NPsâ properties and some synthesis processes. In C
Publicado em: 2008
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4. Caracterização das propriedades ópticas não lineares de vidros teluretos, líquidos orgânicos e colóides de nanopartículas de ouro. / Characterization of the nonlinear optical properties, nonlinear refraction, thermo-optical coefficient, photonics-nonlinear materials.
Nesta tese, investigamos as propriedades ópticas não lineares de quatro sistemas físicos distintos: vidros teluretos, óleo de mamona, líquidos iônicos e colóides de nanopartículas de ouro. Utilizando as técnicas de varredura Z (Z-scan) e varredura de intensidade (I-scan) foi possível determinar os valores das contribuições de origem eletrônica (
Publicado em: 2008
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5. "Estudo das contribuições térmica e eletrônica na variação do índice de refração de materiais dopados com íons emissores" / Study of thermal and electronic contribution to the refractive index variation of materials doped with ions emiters
In this work we have studied the thermal and optical properties of emitters ions by using the thermal lens and z-scan time resolved techniques. It was obtained the thermal lens photothermal spectra of Yb3+ doped samples, and several other photothermal parameters. Also, it was done a study on the optical nonlinearity saturation effects over the determination
Publicado em: 2006
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6. "Não linearidades ópticas em azocompostos" / Optical nonlinearities in azocompounds
This work reports on the temperature dependence of linear and nonlinear properties of azocompounds solutions due to isomerization mechanisms. The dependence of pipi* transitions on the linear structure of azocompounds is already noticeble in the measurements of absorption spectra as function of the temperature for the trans isomer. Knowing the energy levels
Publicado em: 2004
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7. Study of nonlinear optics property of amino acid / Estudo de propriedades ópticas não lineares de aminoácidos
In this work we have studied nonlinear optical properties of amino acids using femtosecond laser pulses. The nonlinear index of refraction (nz) of L-alanine, L-proline, L-serine, L-threonine and L-arginine in aqueous solution have been determined. Also, the influence of pH in the magnitude of nz of amino acids in solution has been studied. Besides, we have d
Publicado em: 2003
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8. Modelos em elementos finitos para a propagação de ondas no dominio espaço temporal
Efficient finite-element formulations for the simulation of ultrashort optical pulses propagating down planar and cylindrical geometries are thoroughly presented. These numerical propagators capable to take into account spatial and temporal effects, are to the best of the author s knowledge original. They solve the scalar transverse electric (TE) and magneti
Publicado em: 2003
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9. On the study of the nonlinear effects of both Self-Phase and Cross-Phase Modulation in optical fibers / Estudo dos Efeitos Não Lineares de Automodulação de Fase e Modulação de Fase Cruzada em Fibras Ópticas
In this work some phenomena that occur during the propagation of pulses of light in optical fibers [1], [7], [13], [16], [18], [20], [21], [22], [24], [25], [59] e [60] are studied. The study is based on the Nonlinear Schrödinger Equation (NLS), gotten in Chapter 2 from the equations of Maxwell, considering a nonlinear susceptibility. The adopted mathematic
Publicado em: 2003
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10. Nonlinear optical properties of aniline oligomers / Propriedades ópticas não-lineares de oligômeros de anilina
We report on the study of electronic optical non linearities in two aniline oligomers: dimer and the tetramer. Four tetramer concentrations were measured, pure and also 33 and 100% doped; one of dimer non doped another 100% doped. The solutions were prepared using dimethyl sulfoxide (DMSO) as solvent and the doping was performed with hydrochloric acid. The s
Publicado em: 2002
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11. Espectroscopia não linear em cristais fluoretos e polianilina / Nonlinear spectroscopic characterization in fluoride crystals and polyaniline
In this work we studied the effect of nonlinear refraction in Cr+3 doped fluoride host crystals and polymers. The fluoride crystals have been attractive due a broad emission bandwidth and a tunable solid-state lasing in the range of approximately 780-1010 nm. Applying the Thermal Lens (TL) technique, we accomplished a quantitative study of the behavior of th
Publicado em: 2001
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12. Dynamic of optical nonlinearities in macromolecules and oligomers / Dinâmica de não linearidades ópticas em macromoléculas e oligômeros
This work reports the dynamic nonlinear optical properties of organic compounds, namely, ytterbium bis-phthalocyanine, furfuryl alcohol derivatives and azo-aromatic compounds. In order to carry out this investigation we developed an experimental extension to the standard Z-scan technique, named Z-scan with pulse trains. In this method, pulse trains contained
Publicado em: 2000