| 1. |
- L'Huillier, Anne, et al.
(författare)
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High-order Harmonics - A Coherent Source In the Xuv Range
- 1995
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Ingår i: Journal of Nonlinear Optical Physics & Materials. - 0218-1991. ; 4:3, s. 647-665
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Tidskriftsartikel (refereegranskat)abstract
- We review the main results concerning high-order generation processes from the point of view of a potential user of this new source of XUV radiation. The perspectives for optimizing the source, both in efficiency and in spectral range, its characteristics and in particular, its coherence properties, are discussed. Finally, we describe two experiments, which demonstrate the usefulness of the harmonics as a short-pulse, coherent source in the XUV domain.
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| 2. |
- Svanberg, Sune, et al.
(författare)
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Applications of terawatt lasers
- 1994
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Ingår i: LASER SPECTROSCOPY - XITH INTERNATIONAL CONFERENCE. - : AIP. - 1551-7616 .- 0094-243X. - 1563962624 ; :290, s. 264-269
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Konferensbidrag (refereegranskat)
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| 3. |
- Borgstrom, S, et al.
(författare)
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Time-resolved x-ray spectroscopy of optical-field-ionized plasmas
- 1995
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Ingår i: Laser and Particle Beams. - 0263-0346. ; 13:4, s. 459-468
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Tidskriftsartikel (refereegranskat)abstract
- The time-dependent soft X-ray emission of helium and nitrogen plasmas generated by optical-field ionization is reported. The experiments were carried out by focusing pulses of the high-power Ti:sapphire laser of the Lund Institute of Technology (lambda = 796 nm, pulse duration 150 fs, pulse energy 150 mJ) to a 50-mu m diameter spot close to a nozzle, using He and N-2 as target gases. The emission on He+, N4+, and N3+ resonance lines was recorded by means of a flat-field grating spectrometer coupled to an X-ray streak camera. A pronounced difference in the temporal shape of the emission of the Lyman-alpha line of hydrogen-like helium and of the 2p-3d resonance lines of lithium-like and beryllium-like nitrogen was observed. The helium line exhibited an initial spike followed by a slow revival of the emission, whereas the nitrogen lines showed a slow decay after a fast initial rise. These observations are explained with the help of simulations.
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| 4. |
- Steingruber, J, et al.
(författare)
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Prepulse dependence of X-ray emission from plasmas created by IR femtosecond laser pulses on solids
- 1996
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 29:2
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Tidskriftsartikel (refereegranskat)abstract
- We report a strong prepulse dependence of the emission of X-rays from plasmas created by 150 fs Ti:sapphire laser pulses on solids. The laser pulses were focused onto plane samples of aluminium and vanadium with a main pulse power density of about 2.5 x 10(16) W cm(-2). By splitting off a portion of the main pulse we were able to generate a prepulse whose delay and intensity were variable relative to the main pulse. With no prepulse, very weak X-ray radiation from Al9+ and Al10+ was observed, whereas a prepulse to main pulse ratio of more than 0.1% and the prepulse preceding the main pulse by more than 2 ns produced up to 50 times stronger X-ray output.
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| 5. |
- Wahlström, Claes-Göran, et al.
(författare)
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High-order Harmonic-generation In Rare-gases With An Intense Short-pulse Laser
- 1993
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 48:6, s. 4709-4720
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Tidskriftsartikel (refereegranskat)abstract
- We present experimental studies of high-order harmonic generation in the rare gases performed with a short-pulse titanium sapphire laser operating at 794 nm in the 10(14)-10(15) W/cm2 range. The harmonic yields generated in neon and in argon are studied for all orders as a function of the laser intensity. They vary first rather steeply, in the cutoff region, then much more slowly in the plateau region, and, finally, they saturate when the medium gets ionized. The dependence of the high-order harmonic cutoff with the laser intensity in neon and argon is found to be lower than that predicted in single-atom theories. We observe high-order harmonics in argon and xenon (up to the 65th and 45th, respectively) at 10(15) W/cm2, which we attribute to harmonic generation from ions. We also show how the harmonic and fundamental spectra get blueshifted when the medium becomes ionized.
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