| 1. |
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| 2. |
- Johansson, S. G, et al.
(författare)
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Comparison of New Experimental and Astrophysical F-values For Some Ru-ii Lines, Observed In Hst Spectra of Chi-lupi
- 1994
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Ingår i: Astrophysical Journal. - IOP. - 0004-637X. ; 421:2, s. 809-815
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Tidskriftsartikel (refereegranskat)abstract
- We report on experimental absolute oscillator strengths for 18 UV lines of Ru II, obtained by combining laser-induced fluorescence measurements of radiative lifetimes and branching fractions from line intensities in a calibrated Fourier-transform spectrum. HST/GHRS observations of the spectrum of the sharp-lined B star chi Lupi contain six of these lines, for which ''astrophysical'' relative f-values have been determined. The agreement is within 0.10 dex for a Ru abundance of log N(Ru)/N(H) = -7.90, which is 2.3 dex above the solar abundance.
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| 3. |
- Larsson, Jörgen, et al.
(författare)
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Determination of Radiative Lifetimes In the 3snp(1)p(1) Sequence of Mg-i Using Time-resolved Vuv Laser Spectroscopy
- 1993
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Ingår i: Zeitschrift Fur Physik D Atoms, Molecules and Clusters. - 0178-7683. ; 27:4, s. 329-331
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Tidskriftsartikel (refereegranskat)abstract
- The radiative lifetimes of the states in the (n=5-8) 3snp P-1(1) sequence of neutral magnesium were investigated using time-resolved laser-induced fluorescence. Excitation from the 3s2 S-1(0), ground state was performed using VUV radiation, which was produced by resonant sum-difference frequency mixing in a krypton gas cell. We find tau(n=5): 54(3) ns, tau(n=6): 140(10) ns, tau(n=7): 290(20) ns, tau(n=8): 475(40) ns. These results were found to be in fair agreement with a Multi Configuration Hartree-Fock (MCHF) calculation.
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| 4. |
- 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. - 0094-243X. - 1-56396-262-4 ; :290, s. 264-269
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Konferensbidrag (refereegranskat)
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| 5. |
- Svanberg, Sune, et al.
(författare)
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Lund High-power Laser Facility - Systems and 1st Results
- 1994
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Ingår i: Physica Scripta. - 0281-1847. ; 49:2, s. 187-197
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Tidskriftsartikel (refereegranskat)abstract
- A high-power laser facility has been established at the Lund Institute of Technology, Sweden, available to national groups and their international collaboration partners. The laboratory incorporates three major 10 Hz laser systems, that can be operated individually or synchronized in combined use. Each system represents extreme optical powers in a certain sense. The main system is a terawatt laser based on chirped pulse amplification in titanium doped sapphire. It generates radiation tunable in the 760-840 nm region with a maximum power of 1.5TW in 150 fs long pulses. A further system is set up to generate nanosecond pulses of extremely bright VUV radiation (down to 120 nm) by sum-difference four-wave mixing in krypton gas. Finally, a third system generates widely tunable radiation (200-900 nm) of a pulse duration of 10's of picoseconds. The experimental areas incorporate target chambers, spectrometers and fast electronics. The systems have been used in a number of experiments requiring high optical powers, and a brief account of the initial activities is given. Detailed studies of high-harmonic generation in inert gases are reported as well as the generation and application of hard X-rays from microplasmas. Intense white-light generation by self-phase modulation in water has been used for biological tissue studies and for chemical pump/probe experiments. VUV radiation has been used for studies of radiative properties of excited states of free atoms. Finally, the picosecond laser system has been utilized in studies of the temporal structure of harmonics from an inert gas and for soft X-ray generation for high-resolution microscopy. A discussion section concludes the presentation.
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| 6. |
- 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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