Ultrashort Pulse
Mostrando 13-24 de 26 artigos, teses e dissertações.
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13. Amplificadores Ãpticos, estudos de polarizaÃÃo e geraÃÃo de pulso usando processos paramÃtricos em fibras Ãpticas
The recent telecommunication development can be, to a large extent, attributed to the capacity of transmitting information (video, sound and data) at high transmission rates (Tbits/s) through the optical fiber. The constant advances in the technological development of active and passive devices based on optical fibers have enabled a steady increase in commun
Publicado em: 2007
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14. Chaveamento de pulsos ultracurtos em grades de Bragg não-lineares de fibras ópticas. / Ultrashort Pulse Switching through Nonlinear Fiber Bragg Gratings
Grades de Bragg não-lineares têm sido consideradas desde o final do século passado para aplicações em sistemas de comunicações ópticas e sensoriamento. O estudo de pulsos ultra-curtos em grades de Bragg lineares, entretanto, só tem sido considerado nos últimos anos, devido ao desenvolvimento de técnicas numéricas específicas para se resolver o p
Publicado em: 2006
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15. Development of a Cr:LISAF ultrashort pulse amplifier for a high hybrid laser system / "Desenvolvimento de um amplificador de pulsos ultracurtos de Cr:LiSAF para um sistema laser híbrido de alta potência"
Foi desenvolvida e construída uma cavidade bombeadora para um meio de ganho de Cr:LiSAF na forma de bastão, bombeado por duas lâmpadas, visando sua operação como amplificador de pulsos ultracurtos a taxas de repetição elevadas, e com redução da carga térmica sobre o meio de ganho. A cavidade e o meio de ganho foram caracterizados sob operação com
Publicado em: 2006
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16. Estudo do desempenho de acoplador direcional não linear duplo assimétrico de fibras ópticas operando portas lógicas. / Study of the performance of assymmetrical two-core non linear directional fiber coupler operating logic gates
We investigate the performance of three different non linear directional assymmetrical fibers couplers that include a profile of self-modulation of increasing and decreasing phase. The asymmetry is associated with the profile of self-modulation of phase of one of the chanels. Initially, we investigate the performance of the considered coupler using ultrashor
Publicado em: 2006
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17. Ultrashort pulse optimization via two-photon absorption / "Otimização de pulsos ultracurtos via absorção de dois fótons"
Este trabalho teve como objetivo a montagem de um sistema de otimização de pulsos ultracurtos (oscilador laser modelocked de 15 fs), através de uma técnica de formatação de pulsos via absorção de dois fótons em compostos orgânicos. Está técnica utiliza uma estratégia evolucionária baseada em um algoritmo genético, onde se controla o formato do
Publicado em: 2005
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18. Controle coerente em Ãtomos de Rb por manipulaÃÃo da fase de pulsos ultracurtos
Coherent quantum control aims to drive a quantum system towards a desired final state. Nowadays its study is widely employed to manipulate transitions in atomic systems, to break molecular bonds and to optimize the output of chemical reactions, for instance. In this thesis experimental and theoretical results of partial temporal coherent control in two diffe
Publicado em: 2005
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19. ULTRA-SHORT OPTICAL PULSES GENERATION USING RATIONAL MODE-LOCKING IN FIBER LASERS / GERAÇÃO DE PULSOS ÓPTICOS ULTRACURTOS USANDO A TÉCNICA DE MODE-LOCKING RACIONAL EM LASERS A FIBRA
This work describes a simple and stable harmonically mode- locked erbium-doped fiber ring laser, that produces high power, ~ 1 ps transform-limited sech optical pulses. Pulse trains with different high repetition rates were obtained using harmonic mode-locking and rational harmonic mode- locking techniques. The temporal and spectral characteristics of the pu
Publicado em: 2000
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20. Aplicações de fibras opticas na geração de pulsos opticos ultracurtos
We have investigated picosecond nonlinear processes in optical fibers and their applications to ultrashort light pulse generation. Several experiments were performed in which we studied the role of stimulated Raman scattering, self and cross-phase modulation combined with group velocity dispersion on the generation of u1trashort pulses. In the first experime
Publicado em: 1990
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21. Estudo de fenomonos ultra-rapidos
In this work process of ultrashort light pulses generation from a colliding pulse modelocked laser was studied. A model was developed wick explains how a frequency sweep is generated in the pulse on propagation through the saturable absorber. Using this laser, the hot carrier thermalization time in a electrodeposited CdSe film was measured in a pump and prob
Publicado em: 1989
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22. Chaves optoeletronicas de alta tensão a semicondutor
In this work we have studied a semiconductor optoelectronic device to switch high-voltage electrical pulses ( >500 V). The semiconductors used were semi-isolant GaAs and InP that show high-resistivity (>107 W.cm) To switch activation we have built a nitrogen laser that gives pulses of 337.1 nm radiation and duration of 2 ns. We have studied the effects of la
Publicado em: 1988
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23. Chaves eletricas a semicondutor controladas por pulsos laser de picosegundos
In this work we have studied the construction of ultra-fast electrical switches activated by ultrashort laser pulses. Such devices, built based on high-resistivity semiconductors, transform the energy of ultra short light pulses in electrical signals. These signals have rise time and pulse width of the order of pico-seconds. Parameters concerning the constru
Publicado em: 1984
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24. Pulse confinement in optical fibers with random dispersion
Short-range correlated uniform noise in the dispersion coefficient, inherent in many types of optical fibers, broadens and eventually destroys all initially ultra-short pulses. However, under the constraint that the integral of the random component of the dispersion coefficient is set to zero (pinned), periodically or quasi-periodically along the fiber,
The National Academy of Sciences.