| 1. |
- Faldon, M. E, et al.
(författare)
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Studies of time-resolved harmonic generation in intense laser fields in xenon
- 1992
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Ingår i: Journal of the Optical Society of America B: Optical Physics. - 0740-3224. ; 9:11, s. 2094-2099
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Tidskriftsartikel (refereegranskat)abstract
- We report preliminary experimental and computational studies of the temporal evolution of the harmonics, generated in xenon, by 50-ps pulses from a Nd: YLF laser, amplified in Nd: glass amplifiers, and focused to produce intensities in the range 1013--5 {\texttimes} 1013 W cm{\textminus}2. Measurements were made of the temporal profiles of the seventh- and ninth-order harmonics using a specially modified VUV streak camera with better than 7-ps temporal resolution. These results were compared with predictions of a numerical model that included the effects of neutral atom depletion and photoelectron dispersion in the calculation of the harmonic output as a function of time.
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| 2. |
- Starczewski, Tomas, et al.
(författare)
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Time-resolved Harmonic-generation In An Ionizing Gas
- 1994
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 27:14, s. 3291-3301
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Tidskriftsartikel (refereegranskat)abstract
- We report on a time-resolved study of the fifth harmonic generated in xenon by 140 ps pulses from a Nd:YAG laser in the 10(13) W cm-2 intensity regime. Absolute timing between the driving laser pulse and the harmonic pulse could be determined by means of reference harmonics generated in non-linear crystals and a single common streak camera. Above a certain laser intensity the centre of the observed harmonic pulse was shifted earlier in time relative to the laser pulse. We found the intensity dependence of this shift to be approximately linear within the intensity range used which is consistent with the results of numerical simulations taking the ionization and dispersion of the xenon gas into account.
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| 3. |
- Muffett, J. E, et al.
(författare)
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Numerical Modeling of the Spatial Profiles of High-order Harmonics
- 1994
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 27:23, s. 5693-5706
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Tidskriftsartikel (refereegranskat)abstract
- The far-field spatial distributions of high-order harmonics in an ionized medium have been investigated using a computer model that includes both the single atom effects and the collective effects of the medium. The results show that depletion of the non-linear medium due to ionization and radial phase variations across the gas jet cause broadening and complicated structures in the far-field spatial distributions. These phase variations are due to three factors: focusing, ionization, i.e. depletion of the non-linear medium and electron dispersion, and intensity-dependent phase variations of the atomic dipoles.
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