11. Towards ultrafast X-ray condensed matter physics with MHz repetition rate HHG sourcesJurij Urbančič, 2015, objavljeni povzetek znanstvenega prispevka na konferenci Opis: In recent years, an increasing number of ultrafast material science experiments are based on the use of table-top high-harmonic generation (HHG) lightsources [1,2]. Despite the huge success of these first experiments, a major drawback has been the limited repetition rate of these lightsources, in particular with respect to all types of photoemission experiments. Here, we combine newly developed high-repetition rate HHG sources [3,4] with state-of-the-art element-specific magneto-optical Kerr experiments. The chances and prospects for future ultrafast materials science experiments with these lightsources will be discussed.
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Povzetek najdenega: ...are based on the use of table-top high-harmonic generation (HHG) lightsources [1,2]. Despite the huge...
Ključne besede: High Harmonic Generation, X-Rays, Condensed Matter
Objavljeno: 22.05.2020; Ogledov: 2250; Prenosov: 0 |
12. The role of non-equilibrium dynamics in photo-induced phase transitions of correlated materialsJurij Urbančič, 2015, objavljeni povzetek znanstvenega prispevka na konferenci Opis: We use femtosecond extreme-ultraviolet time- and angle-resolved photoelectron spectroscopy to study the ultrafast photo-induced suppression of the charge-density wave (CDW) in 1T-TiSe2. In the following non-equilibrium electron dynamics after femtosecond laser excitation, we see that hot-carrier multiplication is the primary driver for the ultrafast CDW suppression. As soon as the optically excited carriers have relaxed to a quasi-equilibrium hot Fermi-distribution electron gas, the CDW suppression stops. Theoretical calculations of the hot-carrier scattering processes and the screening properties further link the carrier multiplication to the observed CDW gap dynamics.
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Povzetek najdenega: ...Correlated Materials, High Harmonic Generation, ARPES...
Ključne besede: Correlated Materials, High Harmonic Generation, ARPES
Objavljeno: 22.05.2020; Ogledov: 2089; Prenosov: 0 |
13. Element-resolved study on the influence of a magnetic dopant on the exchange interaction in FePt on ultrashort timescalesJurij Urbančič, 2017, objavljeni povzetek znanstvenega prispevka na konferenci Opis: In this study, we investigate the optically induced ultrafast demagnetization dynamics of a FePt alloy doped with Mn atoms on the characteristic timescale of the exchange interaction of a few femtoseconds. We use high harmonic generation with photon energies in the XUV to gain elemental resolution in a femtosecond magneto-optical Kerr-effect experiment [1] in transversal geometry. Following up on earlier experiments, which showed the importance of the exchange interaction in the demagnetization process in alloys [2,3], we see clear differences in the dynamical responses of the three elements Fe, Pt, and Mn. Our results suggest, that the exchange coupling between the magnetic moments of the FePt alloy and the Mn dopant changes on ultrashort timescales.
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Povzetek najdenega: ...a few femtoseconds. We use high harmonic generation with photon energies in the XUV to...
Ključne besede: FePt, High Harmonic Generation, Laser, Magnetic Materials
Objavljeno: 22.05.2020; Ogledov: 2204; Prenosov: 0 |
14. Coupling of autoionizing states by a chirped laser pulseBarbara Ressel, Jurij Urbančič, Primož Rebernik Ribič, Špela Krušič, Žiga Barba, Mateja Hrast, Klemen Bučar, Andrej Mihelič, Matjaž Žitnik, Matija Stupar, David Gauthier, Giovanni De Ninno, 2020, objavljeni povzetek znanstvenega prispevka na konferenci Opis: We have observed the autoionization of the laser-coupled 2s2p 1Po and 2p2 1Se resonances in helium. The ions were collected while varying the frequency and delay of the extreme-ultraviolet (EUV) excitation pulse with respect to the linearly chirped visible (VIS) laser pulse. From the measured frequency-delay map the Autler- Townes splitting, the EUV-VIS cross-correlation and the linear chirp parameter were extracted.
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Ključne besede: High Harmonic Generation
Objavljeno: 29.06.2020; Ogledov: 2242; Prenosov: 0
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