Laser Focusing
Mostrando 1-12 de 19 artigos, teses e dissertações.
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1. A química analítica aplicada aos estudos de pigmentos rupestres: uma revisão
Instrumental advances have been employed in the study of archeological remains such as prehistoric rupestrians paintings with the objective of chemically characterizing them in order to reconstruct the cultural technologies of a prehistoric human group and/or to support conservation science studies. The analytical techniques most commonly used in archaeometr
Química Nova. Publicado em: 2022
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2. Estudo experimental da refração não linear em vapor de césio utilizando a técnica z-scan
The z-scan technique consists in measurement of the variation of the radial intensity of a Gaussian laser beam induced by self-focusing or self-defocusing while propagating through a nonlinear medium. These variations are deduced through detection of the beam transmitted through a small, fixed aperture. After the seminal work by Sheik-Bahae et al. [30] in 19
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 13/10/2011
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3. Efeito da fluência na análise de pastilhas de materiais vegetais por espectrometria de emissão óptica com plasma induzido por laser / Effect of fluence on laser induced breakdown spectrometry analysis of pellets of plant materials
A espectrometria de emissão óptica com plasma induzido por laser (LIBS) constitui um método alternativo para a determinação simultânea de macro e micronutrientes em pastilhas de materiais vegetais. No entanto, pouca informação com relação às condições de fluência e de focalização do laser mais apropriadas para a análise de pastilhas de mater
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 10/02/2011
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4. 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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5. Construction and evaluation of a laser induced breakdown spectroscopy instrument: application in alloy samples / Construção e avaliação de um instrumento para espectroscopia de emissão em plasma induzido por laser (LIBS) : aplicação em ligas metalicas
In this work a time resolved LIBS instrument (TRELIBS) was built and its performance evaluated in qualitative and quantitative analysis. Additionally, exploratory studies are presented on the influence of parameters that affect the LIBS analysis. The instrument was built employing optical systems and devices of modern technology: an ICCD device, an echelle p
Publicado em: 2007
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6. Laser production of highly charged ions
A summary of ion generation experiments at both low (10(9) W=cm²) and high (10(16) W=cm²) laser intensities, using Nd:YAG and iodine lasers, as well as the properties of the ions produced, are presented. Different medium- and high-Z elements were tested as a target: Ag, Al, Au, Co, Cu, Nb, Ni, Pb, Pt, Sn, Ta, W. A maximum charge state 55+ and maximum energ
Brazilian Journal of Physics. Publicado em: 2004-12
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7. Comparison of two multipass configurations for scattered light amplification
Scattered light amplification by using multipass method is a very useful technique to increase Thomson and Rayleigh scattering signals for local plasma electron temperature and density measurements. Using Rayleigh scattering in nitrogen neutral gas chamber, the well-known technique of multipass system with two concentrical spherical mirrors is compared with
Braz. J. Phys.. Publicado em: 2001-09
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8. New applications of photothermal techniques for studying interfaces. / Novas aplicações de técnicas fototérmicas para o estudo de interfaces.
This work presents the development of new instrumentations based on photothermal phenomena to study solid-liquid and liquid-gas interfaces, including in the latter the effect of surfactants. The work is divided into chapters, each one focusing on the development and/or application of a new technique. Chapter I presents an introduction to photothermal phenome
Publicado em: 2001
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9. Crescimento seletivo de diamante assistido a laser : um estudo preliminar
The use of diamond films for semiconductor devices promises a technological advance in Electronic Industry. It?s unique combination of properties which overcome that of those semiconductors used nowadays allows a better integration and seed operation in circuits of this particular material. The subject of our Theses is about the growth of a single-crystal di
Publicado em: 1997
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10. Magnetic nanodots from atomic Fe: Can it be done?
Laser focusing of Fe atoms offers the possibility of creating separate magnetic structures on a scale of 10 nm with exact periodicity. This can be done by using the parabolic minima of the potential generated by a standing light wave as focusing lenses. To achieve the desired 10-nm resolution, we need to suppress chromatic and spherical aberrations, as well
The National Academy of Sciences.
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11. Selective destruction of protein function by chromophore-assisted laser inactivation.
Chromophore-assisted laser inactivation of protein function has been achieved. After a protein binds a specific ligand or antibody conjugated with malachite green (C.I. 42,000), it is selectively inactivated by laser irradiation at a wavelength of light absorbed by the dye but not significantly absorbed by cellular components. Ligand-bound proteins in soluti
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12. Generation of ultra-intense single-cycle laser pulses by using photon deceleration
A scheme to generate single-cycle laser pulses is presented based on photon deceleration in underdense plasmas. This robust and tunable process is ideally suited for lasers above critical power because it takes advantage of the relativistic self-focusing of these lasers and the nonlinear features of the plasma wake. The mechanism is demonstrated by part
The National Academy of Sciences.