Laser Beams
Mostrando 1-12 de 38 artigos, teses e dissertações.
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1. Utilizing the Shift-or-Shrink Algorithm to Optimize the Direct Coupling from Laser Diodes to Diffused Channel Waveguides
Abstract Several formulae for computing the direct coupling efficiencies from laser diodes to diffused channel waveguides, based on mathematic models for approximating the corresponding laser beams and the waveguiding modes, have been derived in this paper. Then, the authors utilize a simple shift-or-shrink (SOS) algorithm to seek their optimal coupling cond
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-06
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2. Effects of Different Protocols of Low-Level Laser Therapy on Collagen Deposition in Wound Healing
Resumo O laser de baixa potência provou ter sucesso em estimular a produção de colágeno em ensaios de cicatrização de feridas. Entretanto, grande diversidade tem sido observada nos protocolos utilizados. Este trabalho avaliou os efeitos de três protocolos de Terapia a Laser de Baixa Potência (TLBP) na cicatrização de feridas abertas em ratos. Ferid
Braz. Dent. J.. Publicado em: 22/07/2019
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3. Laser cooling techniques: standard and alternated optical molasses
The technique of laser cooling, whose basic idea was proposed in 1975 [1], provided the development of many important areas like high-resolution spectroscopy [2], atomic clocks [3] and quantum gases confined in magnetic or optical traps [4, 5]. Among the techniques applied to cooling neutral atoms is the optical molasses [6] that will be explored in this wor
Rev. Bras. Ensino Fís.. Publicado em: 22/05/2017
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4. The effect of CPP-ACP and Nd:YAG laser on the bond strength of softened dentin
The purpose of this study was to investigate the effect of CPP-ACP treatment and Nd:YAG laser on microtensile bond strength (µTBS) of softened dentin. Sixty samples were obtained from thirty sound third molars. All samples were submitted to dentin softening procedure, by the immersion of the specimens in 30 mL of Sprite Zero for 30min. Afterwards, the sampl
Braz. oral res.. Publicado em: 16/06/2015
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5. 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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6. Localized beams in optical tweezers with conventional and metamaterial particles / Feixes localizados em pinças opticas com particulas convencionasi e metamateriais
In this thesis, we explore some applications of localized beams in FSO - Free Space Optics - and optical tweezers, greater emphasis been given to the second one. For FSO, we show that it is possible to choose the desired longitudinal intensity pattern by using optical elements adequately modeled in their phase functions: the axicons. In this way, these beams
Publicado em: 2009
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7. Construção de uma armadilha magneto-ótica para aplicações em informação quântica e física atômica / Construction of a Magnet-Optical Trap for Aplications at Quantum Information and Atomic Physics
We built a magneto-optical trap (MOT) for rubidium as a first step for the trapping of a cloud of cold atoms in a periodic potential formed by light beams. This system will be used for experiments in atom physics, with possible applications in quantum information. A MOT is necessary to avoid the problems imposed by the thermal agitation of the atoms to the m
Publicado em: 2009
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8. Statistic Techniques applied in dynamic speckle images / TÃCNICAS ESTATÃSTICAS APLICADAS EM IMAGENS DO SPECKLE DINÃMICO
COSTA, Ricardo Marques da. Statistic Techniques applied in dynamic speckle images. 2009. 83 p. Dissertation (Mastering in Systems Engineering) - Universidade Federal de Lavras, Lavras, MG. Analysis of materials through laser beams and application of statistical analysis techniques are now fundamentally important in several science-related fields. In spite of
Publicado em: 2009
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9. Comparison between the digital radiographies through the conventional radiography of periodontal bone reabsorptions / Comparação entre as imagens radiográficas digital com a convencional das reabsorções ósseas periodontais
Comparing the periodontal bone defects, through data obtained with radiographies by the parallelism periapical te chnic, using the conventional and digital images. To obtain the images a x-ray device of the brand Dabi Atlante was used, where the radiographic exam was standardized to obtain a digital and conventional image with the best in detai l and the lea
Publicado em: 2009
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10. Multicolor Quantum Correlations in the Optical Parametric Oscillator / Correlações quânticas multicolores no oscilador paramétrico ótico
We have investigated the collective quantum properties of the three bright light beams produced by an optical parametric oscillator (OPO) operating above threshold, named pump, signal, and idler. We have analyzed experimentally their intensity and phase quantum fluctuations, and how they are correlated. For the first time, we have observed the existence of p
Publicado em: 2008
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11. Efeitos coerentes no acoplamento dos lasers de fentosegundo e de diodo em vapor de rubÃdio
Mode-locked, phase-stabilized femtosecond (fs) lasers with high-repetition rate produce a frequency standard composed by a great number of narrow modes, known as frequency comb. The interaction of inhomogeneously broadened two-level systems with a train of fs pulses, for the case in which the atomic relaxation times are longer than the laser repetition perio
Publicado em: 2008
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12. Acoplamento de dois feixes com lasers de femtossegundos em vapor de Rb
Femtosecond lasers operating in the mode-locked regime have a repetition rate determined by the round trip time of the pulse inside the laser cavity (TR = 2L/c). For Ti:sapphire lasers the repetition rate is typically of the order of 100 MHz, with TR 10 ns. Under this condition TR may be smaller then the population relaxation time (T1) and the coher
Publicado em: 2007