85 resultados para femtosecond pulses


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A mode for generating a sequence of spectrally limited pulses with a duration of 2 nsec and a repetition frequency of approximately 100 GHz in AlGaAs/GaAs by an injection heterolaser, which has amplifying and absorbing parts combined in a common resonator, is discussed.

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A new dynamic regime in a multisegmented AlGaAs/GaAs DH injection laser has been realised. Generation of bandwidth-limited 100 GHz repetition rate pulses has been demonstrated. This value is claimed to be the largest ever reported for an ultrashort pulse repetition frequency obtained directly from a laser.

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An Agat-SF linear-scan streak image-converter camera was used to record output pulses of 2. 7 psec duration generated by an injection laser with an external dispersive resonator operated in the active mode-locking regime. The duration of the pulses was determined by the reciprocal of the spectral width and the product of the duration and the spectral width was 0. 30.

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Pulses of 15 psec duration were generated by an injection laser with an external dispersive resonator operating in the active mode-locking regime. This regime was attained by subjecting the laser diode to a current of high frequency equal to the intermode interval in the external resonator. The duration of the pulses was determined by an autocorrelation method in which the second harmonic was generated in an LiIO//3 crystal.

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The variety of laser systems available to industrial laser users is growing and the choice of the correct laser for a material target application is often based on an empirical assessment. Industrial master oscillator power amplifier systems with tuneable temporal pulse shapes have now entered the market, providing enormous pulse parameter flexibility in an already crowded parameter space. In this paper, an approach is developed to design interaction parameters based on observations of material responses. Energy and material transport mechanisms are studied using pulsed digital holography, post process analysis techniques and finite-difference modelling to understand the key response mechanisms for a variety of temporal pulse envelopes incident on a silicon (1/1/1) substrate. The temporal envelope is shown to be the primary control parameter of the source term that determines the subsequent material response and the resulting surface morphology. A double peak energy-bridged temporal pulse shape designed through direct application of holographic imaging data is shown to substantially improve surface quality. © 2014 IEEE.

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We experimentally demonstrate femtosecond switching of a fully packaged hybrid-integrated Mach-Zehnder switch. A record switching window of 620fs at full-width-half-maximum is achieved. © 2004 Optical Society of America.

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The focused beam of a 100 fs, 800 nm laser is used to induce a spark in some laminar premixed air-methane flames operating with variable fuel content (equivalence ratio). The analysis of the light escaping from the plasma revealed that the Balmer hydrogen lines, H α and H β, and some molecular origin emissions were the most prominent spectral features, while the CN (B 2Σ +-X 2Σ +) band intensity was found to depend linearly with methane content, suggesting that femtosecond laser induced breakdown spectroscopy can be a useful tool for the in-situ determination and local mapping of fuel content in hydrocarbon-air combustible mixtures. © 2012 American Institute of Physics.