| 1. |
- Arnold, C. L., et al.
(author)
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The ELI-ALPS secondary sources : A getaway to scientific excellence
- 2013
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In: 2013 Conference on Lasers and Electro-Optics, CLEO 2013. - 9781557529725 ; 2013
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Conference paper (peer-reviewed)abstract
- The essence of ELI-ALPS, the laser driven secondary sources ranging from X-ray and X-UV to THz with duration as short as tens of attoseconds, are designed to be available for users from 2016.
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| 2. |
- Vismarra, F., et al.
(author)
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Isolated Attosecond Pulse Generation Driven by Spatio-Temporal Pulse Reshaping in a Semi-infinite Gas Cell
- 2023
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In: 2023 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2023. - 9798350345995
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Conference paper (peer-reviewed)abstract
- High-order harmonic generation (HHG) is an ubiquitous tool of great interest in many fields of research from imaging to ultrafast spectroscopy [1]. In its most common implementation, an intense (≈ 1014 W/cm2) infrared (IR) pulse is focused on a noble gas target yielding a train of attosecond pulses in the extreme ultraviolet (XUV) spectral region. By adopting proper strategies and target geometries, it is possible to isolate an attosecond pulse out of the train. In this work, we demonstrate the generation of isolated attosecond pulses by spatio-temporal reshaping of few-cycle IR driving pulses in a semi-infinite gas cell. We combine numerical simulations and experiments to investigate the interplay between the spatio-temporal reshaping of the driving field, the generation of harmonics and the isolation of an attosecond pulse.
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| 5. |
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| 6. |
- Sansone, G., et al.
(author)
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Attosecond excitation of electron wavepackets
- 2008
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In: Quantum Electronics and Laser Science Conference, QELS 2008. - 9781557528599
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Conference paper (peer-reviewed)abstract
- We present experiments, supported by time-dependent Schrödinger simulations, on the dynamics of Helium bound states after an attosecond excitation in the presence of a strong infrared laser field.
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| 7. |
- Sansone, G., et al.
(author)
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Electron localization following attosecond molecular photoionization
- 2010
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 465:7299, s. 3-763
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Journal article (peer-reviewed)abstract
- For the past several decades, we have been able to directly probe the motion of atoms that is associated with chemical transformations and which occurs on the femtosecond (10(-15)-s) timescale. However, studying the inner workings of atoms and molecules on the electronic timescale(1-4) has become possible only with the recent development of isolated attosecond (10(-18)-s) laser pulses(5). Such pulses have been used to investigate atomic photoexcitation and photoionization(6,7) and electron dynamics in solids(8), and in molecules could help explore the prompt charge redistribution and localization that accompany photoexcitation processes. In recent work, the dissociative ionization of H-2 and D-2 was monitored on femtosecond timescales(9) and controlled using few-cycle near-infrared laser pulses(10). Here we report a molecular attosecond pump-probe experiment based on that work: H-2 and D-2 are dissociatively ionized by a sequence comprising an isolated attosecond ultraviolet pulse and an intense few-cycle infrared pulse, and a localization of the electronic charge distribution within the molecule is measured that depends-with attosecond time resolution-on the delay between the pump and probe pulses. The localization occurs by means of two mechanisms, where the infrared laser influences the photoionization or the dissociation of the molecular ion. In the first case, charge localization arises from quantum mechanical interference involving autoionizing states and the laser-altered wavefunction of the departing electron. In the second case, charge localization arises owing to laser-driven population transfer between different electronic states of the molecular ion. These results establish attosecond pump-probe strategies as a powerful tool for investigating the complex molecular dynamics that result from the coupling between electronic and nuclear motions beyond the usual Born-Oppenheimer approximation.
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| 8. |
- Kelkensberg, F., et al.
(author)
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Molecular Dissociative Ionization and Wave-Packet Dynamics Studied Using Two-Color XUV and IR Pump-Probe Spectroscopy
- 2009
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In: Physical Review Letters. - 1079-7114. ; 103:12
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Journal article (peer-reviewed)abstract
- We present a combined theoretical and experimental study of ultrafast wave-packet dynamics in the dissociative ionization of H-2 molecules as a result of irradiation with an extreme-ultraviolet (XUV) pulse followed by an infrared (IR) pulse. In experiments where the duration of both the XUV and IR pulses are shorter than the vibrational period of H-2+, dephasing and rephasing of the vibrational wave packet that is formed in H-2+ upon ionization of the neutral molecule by the XUV pulse is observed. In experiments where the duration of the IR pulse exceeds the vibrational period of H-2+ (15 fs), a pronounced dependence of the H+ kinetic energy distribution on XUV-IR delay is observed that can be explained in terms of the adiabatic propagation of the H-2+ wave packet on field-dressed potential energy curves.
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| 9. |
- Klünder, Kathrin, et al.
(author)
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Reconstruction of attosecond electron wave packets using quantum state holography
- 2013
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In: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 88:3
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Journal article (peer-reviewed)abstract
- We present a method for performing quantum state holography, with which we completely characterize the amplitude and phase of an attosecond electron wave packet. Our approach is an extension of a recent publication [J. Mauritsson et al., Phys. Rev. Lett. 105, 053001 (2010)] in which we demonstrated experimentally that the energies and amplitudes of an attosecond electron wave packet can be characterized using attosecond electron interferometry. Here we show theoretically that attosecond electron interferometry can be extended to retrieve the phases of all the states that make up the wave packet. We demonstrate the feasibility of our method by analyzing a wave packet created by a shake-up process. We show that our method can successfully retrieve arbitrary phases and/or lifetimes added to the component eigenstates.
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| 10. |
- Mauritsson, Johan, et al.
(author)
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Attosecond Electron Spectroscopy Using a Novel Interferometric Pump-Probe Technique
- 2010
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In: Physical Review Letters. - 1079-7114. ; 105:5
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Journal article (peer-reviewed)abstract
- We present an interferometric pump-probe technique for the characterization of attosecond electron wave packets (WPs) that uses a free WP as a reference to measure a bound WP. We demonstrate our method by exciting helium atoms using an attosecond pulse (AP) with a bandwidth centered near the ionization threshold, thus creating both a bound and a free WP simultaneously. After a variable delay, the bound WP is ionized by a few-cycle infrared laser precisely synchronized to the original AP. By measuring the delay-dependent photoelectron spectrum we obtain an interferogram that contains both quantum beats as well as multipath interference. Analysis of the interferogram allows us to determine the bound WP components with a spectral resolution much better than the inverse of the AP duration.
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| 11. |
- Kühn, Sergei, et al.
(author)
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The ELI-ALPS facility : The next generation of attosecond sources
- 2017
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In: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 50:13
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Research review (peer-reviewed)abstract
- This review presents the technological infrastructure that will be available at the Extreme Light Infrastructure Attosecond Light Pulse Source (ELI-ALPS) international facility. ELI-ALPS will offer to the international scientific community ultrashort pulses in the femtosecond and attosecond domain for time-resolved investigations with unprecedented levels of high quality characteristics. The laser sources and the attosecond beamlines available at the facility will make attosecond technology accessible for scientists lacking access to these novel tools. Time-resolved investigation of systems of increasing complexity is envisaged using the end stations that will be provided at the facility.
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