Yazar "Strohaber, J." seçeneğine göre listele

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    Öğe
    Spatio-temporal control of femtosecond laser filamentation and white-light generation
    (American Institute of Physics Inc., 2017) Kaya, N.; Kaya, G.; Strohaber, J.; Kolomenskii, A.; Schuessler, H.
    Several possibilities are investigated to control spatio-temporal characteristics of the femtosecond filamentation process and the resulting white-light generation. We controlled the development of self-focusing, and resulting locations of filaments producing white-light in water by changing the transverse spatial phase of an initial Gaussian beam with a computer generated holographic technique and a spatial light modulator. We studied intense femtosecond filamentation and propagation of femtosecond pulses with different transverse modes in water. The filament propagation length was found to increase with Bessel-Gaussian modes of the beams, when more lateral lobes were used, under the conditions of the same peak intensity, pulse duration, and size of the central peak of the incident beam. We also investigated variations of white-light generation when the delay between the two pulses was varied. With a decrease of the relative delay, an enhancement of white-light output was observed, which at near-zero delays was reverted to a suppression of white-light generation. © 2017 Author(s).
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    Öğe
    Time slicing in 3D momentum imaging of the hydrogen molecular ion photo-fragmentation
    (Amer Inst Physics, 2017) Kaya, N.; Kaya, G.; Pham, F. V.; Strohaber, J.; Kolomenskii, A. A.; Schuessler, H. A.
    Photo-fragmentation of the hydrogen molecular ion was investigated with 800 nm, 50 fs laser pulses by employing a time slicing 3D imaging technique that enables the simultaneous measurement of all three momentum components which are linearly related with the pixel position and slicing time. This is done for each individual product particle arriving at the detector. This mode of detection allows us to directly measure the three-dimensional fragment momentum vector distribution without having to rely on mathematical reconstruction methods, which additionally require the investigated system to be cylindrically symmetric. We experimentally reconstruct the laser-induced photo-fragmentation of the hydrogen molecular ion. In previous experiments, neutral molecules were used as a target, but in this work, performed with molecular ions, the initial vibrational level populations are well-defined after electron bombardment, which facilitates the interpretation. We show that the employed time-slicing technique allows us to register the fragment momentum distribution that reflects the initial molecular states with greater detail, revealing features that were concealed in the full time-integrated distribution on the detector. Published by AIP Publishing.