Pump Probe Technique
Mostrando 1-12 de 20 artigos, teses e dissertações.
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1. Microscopía fototérmica para el estudio de transformaciones de fase
ABSTRACT A novel system allowing a high spatial resolution mapping of the thermal diffusivity as a function of temperature up to 1800 K is presented. The system is based on a photothermal technique recently developed by the group, consisting in measuring, with a probe laser beam, the curvature induced by local heating with a modulated pump laser. A microscop
Matéria (Rio J.). Publicado em: 19/07/2018
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2. Espectroscopia ultrarrápida do polímero semicondutor luminescente MEH-PPV com excitação no ultravioleta / Ultrafast spectroscopy of the luminescent semiconducting polymer MEH-PPV with ultraviolet excitation
The optoelectronics industry is currently undergoing a transition period in which inorganic materials are being replaced by organic materials, oligomers and polymers, in the fabrication of some types of devices. However, factors such as low efficiency and low lifetime prevent polymer based devices on entering the market definitely. The solution of these issu
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 17/08/2012
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3. Síntese, caracterização microestrutural e elétrica de compostos cerâmicos à base de soluções sólidas de titanato de estrôncio, titanato de cálcio e óxido de ferro / Synthesis, microstructural and electrical characterization of ceramic compounds based on strontium and calcium titanates and iron-oxide
CaxSr1-xTi1-yFeyO3-δ, x = 0, 0.5 and 1.0, y = 0 and 0.35, ceramic compounds were synthesized by reactive solid state synthesis of CaCO3, SrCO3, TiO2 and Fe2O3, and by the polymeric precursor technique. The ceramic powders were evaluated by thermogravimetry and differential thermal analysis, X-ray diffraction and scanning electron microscopy. Sintered c
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 19/09/2011
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4. Técnica de bombeio e prova para medidas de absorção de estado excitado e de emissão estimulada, em materiais sólidos dopados com íons terras raras
Rare earth ion doped solid state materials are the most important active media of near-infrared and visible lasers and other photonic devices. In these ions, the occurrence of Excited State Absorptions (ESA), from long lived electronic levels, is commonplace. Since ESA can deeply affect the efficiencies of the rare earth emissions, evaluation of these transi
Química Nova. Publicado em: 2008
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5. Propriedades magnÃticas e Ãpticas de filmes finos rugosos
In this dissertation we study the influence of susbtrate roughness on the magnetic and optical properties of polycrystalline permalloy (Py) films and the optical properties of thin silver (Ag) films, when deposited on this support. The surface roughness of the glass substrates was generated by chemical attack with high concentration flouridic acid vapor (HF-
Publicado em: 2008
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6. Decoherence and relaxation time in an ensemble of quantum dots / Tempos de relaxação e decoerencia em ensembles de pontos quanticos
Experimental measurements were carried out to determine the scales of the relaxation and decoherence time for the electronic spin as quantum bit. The structure of the exciton states was investigated with the objective to serve as intermediate states in the spin manipulation. The system studied for the implementation of the quantum computation is an ensemble
Publicado em: 2007
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7. ABLAÇÃO CIRÚRGICA DOS BULBOS OLFATÓRIOS EM COELHOS: MODELO PARA ESTUDOS DE PATOGENIA DE INFECÇÕES POR VÍRUS NEUROTRÓPICOS / SURGICAL ABLATION OF THE OLFACTORY BULB IN RABBITS: A MODEL TO STUDY THE PATHOGENISIS OF NEUROTROPIC VIRUS INFECTIONS.
Rabbits have been used as animal models to study the pathogenesis of neurological infection by bovine herpesvirus type 5 (BHV-5), an important agent of meningoencephalitis in cattle. The olfactory system has been implicated as the main pathway for the virus to reach the brain after replication in the nasal mucosa. To investigate the role of the olfactory rou
Publicado em: 2006
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8. CHARACTERISATION OF ALLOPTICAL WAVELENGTH CONVERSION BY CROSS-GAIN MODULATION IN SEMICONDUCTOR OPTICAL AMPLIFIERS / CARACTERIZAÇÃO DA CONVERSÃO DE COMPRIMENTO DE ONDA POR MODULAÇÃO DE GANHO CRUZADO EM AMPLIFICADORES ÓPTICOS SEMICONDUTORES
Wavelength conversion of optical signals by all-optical techniques is an innovative and necessary technology for wavelength routed networks in the near future; the cross-gain modulation method is one of the simplest, in form, to attain this goal. Two categories of the main technique are presented: the classic, also known as pump and probe, and a novel one, n
Publicado em: 2005
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9. "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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10. Study of optical properties of crystalline fibers of CVO:nd3+ and CMO: nd3+/nb5+ / Estudo das propriedades ópticas de fibras cristalinas de CVO:Nd3+ e CMO:Nd3+/Nb5
The present work release an extensive study of spectroscopic properties on CMO:NdNbO4 and CVO:Nd3+ single crystal fibers, in searching for new laser materials activated with diode laser. The fibers were grown by LHPG (laser Heated Pedestal Growth) technique that permits a fast production of fibers with appropriate dimension for mini laser construction, witho
Publicado em: 2003
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11. Fluorescence lifetime imaging by asynchronous pump-probe microscopy.
We report the development of a scanning lifetime fluorescence microscope using the asynchronous, pump-probe (stimulated emission) approach. There are two significant advantages of this technique. First, the cross-correlation signal produced by overlapping the pump and probe lasers results in i) an axial sectioning effect similar to that in confocal and two-p
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12. Resonance Raman spectra of bacteriorhodopsin's primary photoproduct: evidence for a distorted 13-cis retinal chromophore.
We have obtained the resonance Raman spectrum of bacteriorhodopsin's primary photoproduct K with a novel low-temperature spinning sample technique. Purple membrane at 77 K is illuminated with spatially separated actinic (pump) and probe laser beams. The 514-nm pump beam produces a photostationary steady-state mixture of bacteriorhodopsin and K. This mixture