| 1. |
- Ravasio, A, et al.
(författare)
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Single-Shot Diffractive Imaging with a Table-Top Femtosecond Soft X-Ray Laser-Harmonics Source
- 2009
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:2, s. 028104-
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Tidskriftsartikel (refereegranskat)abstract
- Coherent x-ray diffractive imaging is a powerful method for studies on nonperiodic structures on the nanoscale. Access to femtosecond dynamics in major physical, chemical, and biological processes requires single-shot diffraction data. Up to now, this has been limited to intense coherent pulses from a free electron laser. Here we show that laser-driven ultrashort x-ray sources offer a comparatively inexpensive alternative. We present measurements of single-shot diffraction patterns from isolated nano-objects with a single 20 fs pulse from a table-top high-harmonic x-ray laser. Images were reconstructed with a resolution of 119 nm from the single shot and 62 nm from multiple shots.
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| 2. |
- Alexandridi, C., et al.
(författare)
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Attosecond photoionization dynamics in the vicinity of the Cooper minima in argon
- 2021
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Ingår i: Physical Review Research. - 2643-1564. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Using a spectrally resolved electron interferometry technique, we measure photoionization time delays between the 3s and 3p subshells of argon over a large 34-eV energy range covering the Cooper minima in both subshells. The observed strong variations of the 3s−3p delay difference, including a sign change, are well reproduced by theoretical calculations using the two-photon two-color random-phase approximation with exchange. Strong shake-up channels lead to photoelectrons spectrally overlapping with those emitted from the 3s subshell. These channels need to be included in our analysis to reproduce the experimental data. Our measurements provide a benchmark for multielectronic theoretical models aiming at an accurate description of interchannel correlation.
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| 3. |
- Descamps, D, et al.
(författare)
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Extreme ultraviolet interferometry measurements with high-order harmonics
- 2000
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Ingår i: Optics Letters. - 0146-9592. ; 25:2, s. 135-137
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that high-order harmonics generated by short, intense laser pulses in gases provide an interesting radiation source for extreme ultraviolet interferometry, since they are tunable, coherent, of short pulse duration, and simple to manipulate. Harmonics from the 9th to the 15th are used to measure the thickness of an aluminum layer. The 11th harmonic is used to determine the spatial distribution of the electron density of a plasma produced by a 300-ps laser. Electronic densities higher than 2-10(20) electrons/cm(3) are measured. (C) 2000 Optical Society of America. OCIS codes: 190.0190, 190.4160, 190.7110, 120.3180, 140.7240, 350.4500.
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| 4. |
- Merdji, H., et al.
(författare)
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Coherence properties of high-order harmonics : Application to high-density laser-plasma diagnostic
- 2000
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Ingår i: Laser and Particle Beams. - 0263-0346. ; 18:3, s. 495-502
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Tidskriftsartikel (refereegranskat)abstract
- We present two interferometry schemes in the extreme ultraviolet, based on either the wave-front division of a unique harmonic beam (1st scheme) or two spatially separated, phase-locked harmonic sources (2nd scheme). In the first scheme using a Fresnel bimirror interferometer, we measure the degree of spatial coherence of the 13 th harmonic generated in xenon, as a function of different parameters. A high degree of coherence, larger than 0.5, is found for the best conditions in almost the full section of the beam. Then, we demonstrate that the second scheme can be used for interferometry measurements with an ultrahigh time resolution. The 11th harmonic is used to study the spatial variation of the electron density of a laser-produced plasma. Electronic densities higher than 2.10 20 cm -3 are measured.
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