46 results on '"Max-Born-institut, Berlin"'
Search Results
2. UV-induced dissociation of CH2BrI probed by intense femtosecond XUV pulses
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Hansjochen Köckert, Jason W L Lee, Felix Allum, Kasra Amini, Sadia Bari, Cédric Bomme, Felix Brauße, Mark Brouard, Michael Burt, Barbara Cunha de Miranda, Stefan Düsterer, Per Eng-Johnsson, Benjamin Erk, Marie Géléoc, Romain Geneaux, Alexander S Gentleman, Renaud Guillemin, Gildas Goldsztejn, David M P Holland, Iyas Ismail, Loïc Journel, Thomas Kierspel, Jochen Küpper, Jan Lahl, Stuart R Mackenzie, Sylvain Maclot, Bastian Manschwetus, Andrey S Mereshchenko, Terence Mullins, Pavel K Olshin, Jérôme Palaudoux, Francis Penent, Maria Novella Piancastelli, Dimitrios Rompotis, Arnaud Rouzée, Thierry Ruchon, Artem Rudenko, Nora Schirmel, Marc Simon, Simone Techert, Oksana Travnikova, Sebastian Trippel, Claire Vallance, Enliang Wang, Joss Wiese, Farzaneh Ziaee, Tatiana Marchenko, Daniel Rolles, Rebecca Boll, University of Oxford, Deutsches Elektronen-Synchrotron DESY, Physique à Haute Intensité (PHI), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Laboratoire Interactions, Dynamiques et Lasers (ex SPAM) (LIDyl), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Max-Born-institut, Berlin, Dynamique Réactionnelle (DyR), Deutsches Elektronen-Synchrotron [Hamburg] (DESY), Lund University [Lund], Laboratoire Interactions, Dynamiques et Lasers (ex SPAM) (LIDyl), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie Physique - Matière et Rayonnement (LCPMR), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Center for Free-Electron Laser Science (CFEL), Universität Hamburg (UHH), Deutsches Elektronen-Synchrotron [Zeuthen] (DESY), Helmholtz-Gemeinschaft = Helmholtz Association, Saint Petersburg State University (SPBU), Department of Physics and Astronomy [Uppsala], Uppsala University, European XFEL Gmbh, Kansas State University, and ANR-16-CE30-0001,ATTOMEMUCHO,Dynamique électronique attoseconde dans les molécules organiques isolées par la spectroscopie 'core-hole clock'(2016)
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[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Atom and Molecular Physics and Optics ,charge transfer ,free-electron lasers ,Atom- och molekylfysik och optik ,ddc:530 ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,ultrafast molecular dynamics - Abstract
Journal of physics / B 55(1), 014001 (2022). doi:10.1088/1361-6455/ac489d, The ultraviolet (UV)-induced dissociation and photofragmentation of gas-phase CH$_2$BrI molecules induced by intense femtosecond extreme ultraviolet (XUV) pulses at three different photon energies are studied by multi-mass ion imaging. Using a UV-pump���XUV-probe scheme, charge transfer between highly charged iodine ions and neutral CH$_2$Br radicals produced by C���I bond cleavage is investigated. In earlier charge-transfer studies, the center of mass of the molecules was located along the axis of the bond cleaved by the pump pulse. In the present case of CH$_2$BrI, this is not the case, thus inducing a rotation of the fragment. We discuss the influence of the rotation on the charge transfer process using a classical over-the-barrier model. Our modeling suggests that, despite the fact that the dissociation is slower due to the rotational excitation, the critical interatomic distance for charge transfer is reached faster. Furthermore, we suggest that charge transfer during molecular fragmentation may be modulated in a complex way., Published by IOP Publ., Bristol
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- 2022
3. Extracting sub-cycle electronic and nuclear dynamics from high harmonic spectra
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Lukas Miseikis, T. Siegel, Allan S. Johnson, Serguei Patchkovskii, Dane R. Austin, Misha Ivanov, David A. Wood, João Pedro Malhado, Alex G. Harvey, Felicity McGrath, Morgane Vacher, P. G. Hawkins, Olga Smirnova, Zdeněk Mašín, Jon P. Marangos, Clarendon Laboratory [Oxford], University of Oxford [Oxford], University of Bristol [Bristol], Max-Born-institut, Berlin, Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie (MBI), Chimie Et Interdisciplinarité : Synthèse, Analyse, Modélisation (CEISAM), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Engineering & Physical Science Research Council (EPSRC), Commission of the European Communities, and Engineering and Physical Sciences Research Council
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Science ,[SDV]Life Sciences [q-bio] ,chemistry.chemical_element ,02 engineering and technology ,01 natural sciences ,Article ,Spectral line ,Xenon ,Ultrafast photonics ,Ionization ,0103 physical sciences ,Physics::Atomic and Molecular Clusters ,Molecule ,High harmonic generation ,Physics::Atomic Physics ,Physics::Chemical Physics ,010306 general physics ,Spectroscopy ,ComputingMilieux_MISCELLANEOUS ,Physics ,Science & Technology ,Multidisciplinary ,Attosecond science ,Polyatomic ion ,021001 nanoscience & nanotechnology ,Multidisciplinary Sciences ,chemistry ,High-harmonic generation ,Harmonic ,Science & Technology - Other Topics ,Medicine ,[PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph] ,Atomic physics ,0210 nano-technology - Abstract
We present a new methodology for measuring few-femtosecond electronic and nuclear dynamics in both atoms and polyatomic molecules using multidimensional high harmonic generation (HHG) spectroscopy measurements, in which the spectra are recorded as a function of the laser intensity to form a two-dimensional data set. The method is applied to xenon atoms and to benzene molecules, the latter exhibiting significant fast nuclear dynamics following ionization. We uncover the signature of the sub-cycle evolution of the returning electron flux in strong-field ionized xenon atoms, implicit in the strong field approximation but not previously observed directly. We furthermore extract the nuclear autocorrelation function in strong field ionized benzene cations, which is determined to have a decay of $$\tau _0 = 4 \pm 1$$ τ 0 = 4 ± 1 fs, in good agreement with the $$ \tau _0 = 3.5$$ τ 0 = 3.5 fs obtained from direct dynamics variational multi-configuration Gaussian calculations. Our method requires minimal assumptions about the system, and is applicable even to un-aligned polyatomic molecules.
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- 2021
4. Imaging plasma formation in isolated nanoparticles with ultrafast resonant scattering ARTICLES YOU MAY BE INTERESTED IN
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RUPP, Daniela, FLÜCKIGER, Leonie, ADOLPH, Marcus, COLOMBO, Alessandro, GORKHOVER, Tais, HARMAND, Marion, KRIKUNOVA, Maria, MÜLLER, Jan Philippe, OELZE, Tim, OVCHARENKO, Yevheniy, RICHTER, Maria, SAUPPE, Mario, SCHORB, Sebastian, TREUSCH, Rolf, WOLTER, David, BOSTEDT, Christoph, MÖLLER, Thomas, Max-Born-institut, Berlin, Technische Universität Berlin (TU), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Stanford Pulse Institute, Centre d'Etudes Lasers Intenses et Applications (CELIA), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Bordeaux (UB), Deutsches Elektronen-Synchrotron [Hamburg] (DESY), Paul Scherrer Institute (PSI), Technical University of Berlin / Technische Universität Berlin (TU), and Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)
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[PHYS]Physics [physics] ,Physics::Atomic and Molecular Clusters - Abstract
International audience; We have recorded the diffraction patterns from individual xenon clusters irradiated with intense extreme ultraviolet pulses to investigate the influence of light-induced electronic changes on the scattering response. The clusters were irradiated with short wavelength pulses in the wavelength regime of different 4d inner-shell resonances of neutral and ionic xenon, resulting in distinctly different optical properties from areas in the clusters with lower or higher charge states. The data show the emergence of a transient structure with a spatial extension of tens of nanometers within the otherwise homogeneous sample. Simulations indicate that ionization and nanoplasma formation result in a light-induced outer shell in the cluster with a strongly altered refractive index. The presented resonant scattering approach enables imaging of ultrafast electron dynamics on their natural timescale.
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- 2020
5. Nanoscale Imaging of High‐Field Magnetic Hysteresis in Meteoritic Metal Using X‐Ray Holography
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Roberts Blukis, Richard J. Harrison, Bastian Pfau, Christian M. Günther, Piet Hessing, Stefan Eisebitt, Joshua F. Einsle, Pfau, B., 2 Max‐Born‐Institut Berlin Germany, Günther, C. M., 3 Center for Electron Microscopy (ZELMI) Technische Universität Berlin Berlin Germany, Hessing, P., Eisebitt, S., Einsle, J., 5 School of Geographical and Earth Sciences University of Glasgow Glasgow UK, Harrison, R. J., and 6 Department of Earth Sciences University of Cambridge Cambridge UK
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010504 meteorology & atmospheric sciences ,Holography ,538.7 ,engineering.material ,010502 geochemistry & geophysics ,01 natural sciences ,law.invention ,X‐ray holography ,Paramagnetism ,Geochemistry and Petrology ,law ,ddc:550 ,Tetrataenite ,Nanoscopic scale ,0105 earth and related environmental sciences ,cloudy zone ,Condensed matter physics ,X-ray ,Magnetic hysteresis ,Geophysics ,Ferromagnetism ,13. Climate action ,Tazewell meteorite ,Antitaenite ,engineering ,Geology - Abstract
Stable paleomagnetic information in meteoritic metal is carried by the “cloudy zone”: ~1–10 μm‐wide regions containing islands of ferromagnetic tetrataenite embedded in a paramagnetic antitaenite matrix. Due to their small size and high coercivity (theoretically up to ~2.2 T), the tetrataenite islands carry very stable magnetic remanence. However, these characteristics also make it difficult to image their magnetic state with the necessary spatial resolution and applied magnetic field. Here, we describe the first application of X‐ray holography to image the magnetic structure of the cloudy zone of the Tazewell IIICD meteorite with spatial resolution down to ~40 nm and in applied magnetic fields up to ±1.1 T, sufficient to extract high‐field hysteresis data from individual islands. Images were acquired as a function of magnetic field applied both parallel and perpendicular to the surface of a ~100 nm‐thick slice of the cloudy zone. Broad distributions of coercivity are observed, including values that likely exceed the maximum applied field. Horizontal offsets in the hysteresis loops indicate an interaction field distribution with half width of ~100 mT between the islands in their room temperature single‐domain state, providing a good match to first‐order reversal curve diagrams. The results suggest that future models of remanence acquisition in the cloudy zone should take account of strong interactions in order to extract quantitative estimates of the paleofield., Plain Language Summary: Magnetic fields played a significant role in the formation of the solar system and the evolution of the early planetary bodies in the first few million years after solar system formation. Knowledge about magnetic fields in the early solar system can be obtained from meteorites. Some meteorite types contain abundant iron‐nickel alloy that contains nanoscale “cloudy zone” regions (named after their appearance in an optical microscope) that can preserve magnetic information over 4.5 billion years. The cloudy zone is a complex material consisting of magnetically stable nanoscale particles embedded in a nonmagnetic matrix in very close proximity to one another. The fine scale and extreme magnetic stability of the cloudy zone make it challenging to study using conventional magnetic microscopy techniques. Here, we apply X‐ray holography for the first time to image the magnetization of individual magnetic particles and how they respond to magnetic fields. This new approach enables us to measure the magnetic properties of individual nanoscale particles, providing the first direct measurement of their magnetic stability and the strength of particle interactions. These measurements will improve our understanding of the magnetic information carried by the cloudy zone, and of how to extract information about solar system magnetic fields., Key Points: X‐ray holography enables magnetization of natural samples to be imaged with ~40 nm resolution and in applied magnetic fields up to ±1.1 T. Meteoritic cloudy zone consists of strongly interacting single‐domain particles with single‐particle coercivities up to 1 T. Average interaction fields between particles in the cloudy zone are of the order 100–200 mT., European Commission (EC) http://dx.doi.org/10.13039/501100000780, Europen Commission, European Research Council (ERC) http://dx.doi.org/10.13039/501100000781, European Research Council under the European Union's Seventh Framework Programme
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- 2020
6. Electron beam diagnostics for a superconducting radio frequency photoelectron injector
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Will, Ingo [Max-Born-Institut Berlin, MBI, Max-Born-Strasse 2 A, 12489 Berlin (Germany)]
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- 2008
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7. Nonlinear-optical parameters of thin C{sub 60} films at 532 nm
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Priebe, G [Max-Born-Institut, Berlin (Germany)]
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- 2004
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8. All-optical attoclock for imaging tunnelling wavepackets
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Ihar Babushkin, Álvaro Jiménez Galán, José Ricardo Cardoso de Andrade, Anton Husakou, Felipe Morales, Martin Kretschmar, Tamas Nagy, Virgilijus Vaičaitis, Liping Shi, David Zuber, Luc Bergé, Stefan Skupin, Irina A. Nikolaeva, Nikolay A. Panov, Daniil E. Shipilo, Olga G. Kosareva, Adrian N. Pfeiffer, Ayhan Demircan, Mark J. J. Vrakking, Uwe Morgner, Misha Ivanov, Leibniz Universität Hannover=Leibniz University Hannover, Max-Born-institut, Berlin, Vilnius University [Vilnius], Laboratoire Matière sous Conditions Extrêmes (LMCE), DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Modélisation de la matière condensée et des interfaces (MMCI), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Lomonosov Moscow State University (MSU), P. N. Lebedev Physical Institute of the Russian Academy of Sciences [Moscow] (LPI RAS), Russian Academy of Sciences [Moscow] (RAS), and Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany]
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[PHYS]Physics [physics] ,Atom optics ,[SPI]Engineering Sciences [physics] ,FOS: Physical sciences ,General Physics and Astronomy ,[CHIM]Chemical Sciences ,Attosecond Science ,Optics (physics.optics) ,Physics - Optics - Abstract
Recent experiments on measuring time-delays during tunnelling of cold atoms through an optically created potential barrier are reinvigorating the controversial debate regarding possible time-delays during light-induced tunnelling of an electron from an atom. Compelling theoretical and experimental arguments have been put forward to advocate opposite views, confirming or refuting the existence of finite tunnelling time delays. Yet, such a delay, whether present or not, is but a single quantity characterizing the tunnelling wavepacket; the underlying dynamics are richer. Here we propose to augment photo-electron detection in laser-induced tunnelling with detection of light emitted by the tunnelling electron -- the so-called Brunel radiation. Using a combination of single-color and two-color driving fields, we identify the all-optical signatures of the re-shaping of the tunnelling wavepacket as it emerges from the tunnelling barrier and moves away from the core. This reshaping includes not only an effective time-delay but also time-reversal asymmetry of the ionization process, which we describe theoretically and observe experimentally. We show how both delay and reshaping are mapped on the polarization properties of the Brunel radiation, with different harmonics behaving as different hands of a clock moving at different speeds. The all-optical detection paves the way to time-resolving optical tunnelling in condensed matter systems, e.g. tunnelling across bandgaps in solids, on the attosecond time-scale.
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- 2018
9. Photoexcitation Circular Dichroism in Chiral Molecules
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Romain Géneaux, Yann Mairesse, Alex G. Harvey, Valérie Blanchet, Olga Smirnova, Gustavo A. Garcia, Stéphane Petit, Baptiste Fabre, Antoine Comby, Samuel Beaulieu, Dominique Descamps, Laurent Nahon, François Légaré, Zdeněk Mašín, Andres F. Ordonez, Bernard Pons, Centre d'Etudes Lasers Intenses et Applications (CELIA), Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Scientifique [Québec] (INRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Attophysique (ATTO), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Laboratoire Interactions, Dynamiques et Lasers (ex SPAM) (LIDyl), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Max-Born-institut, Berlin, Technical University of Berlin / Technische Universität Berlin (TU), ANR-14-CE32-0014,MISFITS,Imagerie Moléculaire par effet tunnel et recollision en champ fort(2014), ANR-14-CE32-0010,Xstase,Étude du moment angulaire de faisceaux lumineux XUV: synthèse et transferts(2014), European Project: 682978,EXCITERS, European Project: 641789,H2020,H2020-MSCA-ITN-2014,MEDEA(2015), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Bordeaux (UB), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Technische Universität Berlin (TU)
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Chemical Physics (physics.chem-ph) ,Physics ,Circular dichroism ,High Energy Physics::Lattice ,High Energy Physics::Phenomenology ,FOS: Physical sciences ,General Physics and Astronomy ,Metamaterial ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Linear dichroism ,01 natural sciences ,Photoexcitation ,Excited state ,Physics - Chemical Physics ,0103 physical sciences ,Physics - Atomic and Molecular Clusters ,[PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph] ,Atomic physics ,Optical rotation ,Atomic and Molecular Clusters (physics.atm-clus) ,010306 general physics ,0210 nano-technology ,Excitation ,Circular polarization - Abstract
International audience; Chiral effects appear in a wide variety of natural phenomena and are of fundamental importance in science, from particle physics to metamaterials. The standard technique of chiral discrimination—photoabsorption circular dichroism—relies on the magnetic properties of a chiral medium and yields an extremely weak chiral response. Here, we propose and demonstrate an orders of magnitude more sensitive type of circular dichroism in neutral molecules: photoexcitation circular dichroism. This technique does not rely on weak magnetic effects, but takes advantage of the coherent helical motion of bound electrons excited by ultrashort circularly polarized light. It results in an ultrafast chiral response and the efficient excitation of a macroscopic chiral density in an initially isotropic ensemble of randomly oriented chiral molecules. We probe this excitation using linearly polarized laser pulses, without the aid of further chiral interactions. Our time-resolved study of vibronic chiral dynamics opens a way to the efficient initiation, control and monitoring of chiral chemical change in neutral molecules at the level of electrons.
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- 2018
10. Few-femtosecond passage of conical intersections in the benzene cation
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Marc J. J. Vrakking, V. Despré, G. Reitsma, Nikolay V. Golubev, M. C. E. Galbraith, Jochen Mikosch, Horst Köppel, Alexander I. Kuleff, Simona Scheit, Oleg Kornilov, N. Zhavoronkov, Franck Lépine, Max-Born-institut, Berlin, Physikalisch-Chemisches Institut [Heidelberg] (PCI), Universität Heidelberg [Heidelberg], Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
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chemical reaction ,electron ,ultraviolet radiation ,Science ,Attosecond ,General Physics and Astronomy ,probe ,02 engineering and technology ,Hartree calculations ,01 natural sciences ,Article ,experimental study ,General Biochemistry, Genetics and Molecular Biology ,benzene ,[SPI]Engineering Sciences [physics] ,0103 physical sciences ,Physics::Atomic and Molecular Clusters ,[CHIM]Chemical Sciences ,molecular analysis ,Physics::Chemical Physics ,lcsh:Science ,010306 general physics ,[PHYS]Physics [physics] ,Physics ,photochemistry ,Multidisciplinary ,photochemical reactions ,Relaxation (NMR) ,General Chemistry ,Hartree ,021001 nanoscience & nanotechnology ,Internal conversion (chemistry) ,cation ,Excited state ,Femtosecond ,attosecond physics ,benzene cation ,lcsh:Q ,Atomic physics ,0210 nano-technology ,Ultrashort pulse ,Femtochemistry - Abstract
Observing the crucial first few femtoseconds of photochemical reactions requires tools typically not available in the femtochemistry toolkit. Such dynamics are now within reach with the instruments provided by attosecond science. Here, we apply experimental and theoretical methods to assess the ultrafast nonadiabatic vibronic processes in a prototypical complex system—the excited benzene cation. We use few-femtosecond duration extreme ultraviolet and visible/near-infrared laser pulses to prepare and probe excited cationic states and observe two relaxation timescales of 11 ± 3 fs and 110 ± 20 fs. These are interpreted in terms of population transfer via two sequential conical intersections. The experimental results are quantitatively compared with state-of-the-art multi-configuration time-dependent Hartree calculations showing convincing agreement in the timescales. By characterising one of the fastest internal conversion processes studied to date, we enter an extreme regime of ultrafast molecular dynamics, paving the way to tracking and controlling purely electronic dynamics in complex molecules., Attosecond science is beginning to provide the tools to study the previously unattainable crucial first few femtoseconds of photochemical reactions. Here, the authors investigate extremely rapid population transfer via conical intersections in the excited benzene cation, both by experiment and computation.
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- 2017
11. Auto-compression d’impulsions laser de haute énergie dans une fibre creuse à couplage inhibé
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maurel, martin, Debord, Benoît, Husakou, Anton, Gérôme, Frédéric, Benabid, Fetah, Photonique Fibre et Sources Cohérentes (XLIM-PHOT), XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), GLOphotonics S.A.S., Max-Born-institut, and Max-Born-institut, Berlin
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[SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic ,ComputingMilieux_MISCELLANEOUS - Abstract
National audience
- Published
- 2017
12. Source CW de haute puissance et de largeur de raie sub-recoil par diffusion Raman stimulée dans un régime lamb-dicke
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Chafer, Matthieu, Alharbi, Meshaal, Husakou, Anton, Debord, Benoît, Gérôme, Frédéric, Benabid, Fetah A., GLOphotonics S.A.S., Photonique Fibre et Sources Cohérentes (XLIM-PHOT), XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), University of Bath [Bath], Max-Born-institut, and Max-Born-institut, Berlin
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[SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic ,ComputingMilieux_MISCELLANEOUS - Abstract
National audience
- Published
- 2017
13. Strong nonlinear optical effects in micro-confined atmospheric air
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Fetah Benabid, Luca Vincetti, Benoit Debord, Martin Maurel, Frédéric Gérôme, Anton Husakou, Photonique Fibre et Sources Cohérentes (XLIM-PHOT), XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), Department of Information Engineering [Modena], Università degli Studi di Modena e Reggio Emilia (UNIMORE), Max-Born-institut, and Max-Born-institut, Berlin
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Materials science ,hollow core fibers, nonlinear optics, photonics crystal fiber ,business.industry ,Physics::Optics ,Nonlinear optics ,Optical power ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Laser ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Supercontinuum ,law.invention ,010309 optics ,law ,Nonlinear medium ,0103 physical sciences ,Dispersion (optics) ,[SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic ,Optoelectronics ,High harmonic generation ,0210 nano-technology ,business ,Photonic-crystal fiber - Abstract
International audience; Historically, nonlinear optical phenomena such as spectral broadening by harmonic generation have been associated with crystals owing to their strong nonlinear refractive indices, which are in the range of ∼10 −14 cm 2 ∕W. This association was also the result of the limited optical power available from early lasers and the limited interaction length that the laser-crystal interaction architecture could offer. Consequently, these limitations disqualified a large number of materials whose nonlinear coefficient is lower than n 2 ∼10 −16 cm 2 ∕W as suitable materials for nonlinear optics applications. For example, it is a common practice in most of optical laboratories to consider ambient or atmospheric air as a "nonlinear optically" inert medium due to its very low nonlinear coefficient (∼10.10 −19 cm 2 ∕W) and low density. Today, the wide spread of high-power ultra-short pulse lasers on one hand, and low transmission loss and high-power handling of Kagome hollow-core photonic crystal fiber on the other hand, provide the necessary ingredients to excite strong nonlinear optical effects in practically any gas media, regardless of how low its optical nonlinear response is. By using a single table-top 1 mJ ultra-short pulse laser and an air exposed inhibited-coupling guiding hollow-core photonic crystal fiber, we observed generation of supercontinuum and third harmonic generation when the laser pulse duration was set at 600 fs and Raman comb generation when the duration was 300 ps. The supercontinuum spectrum spans over ∼1000 THz and exhibits a typical spectral-density energy of 150 nJ/nm. The dispersion profile of inhibited-coupling hollow-core fiber imprints a distinctive sequence in the supercontinuum generation, which is triggered by the generation of a cascade of four-wave mixing lines and concluded by solitonic dynamics. The Raman comb spans over 300 THz and exhibits multiple sidebands originating from N 2 vibrational and ro-vibrational Raman transitions. With the growing use of hollow-core photonic crystal fiber in different fields, the results can be applied to mitigate air nonlinear response when it is not desired or to use ambient air as a convenient nonlinear medium.
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- 2019
14. Molecular applications of attosecond laser pulses
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Marc J. J. Vrakking, Giuseppe Sansone, Franck Lépine, Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Fisica [Politecnico Milano], Politecnico di Milano [Milan] (POLIMI), and Max-Born-institut, Berlin
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Attosecond ,Degrees of freedom (physics and chemistry) ,Physics::Optics ,General Physics and Astronomy ,02 engineering and technology ,01 natural sciences ,law.invention ,[SPI]Engineering Sciences [physics] ,law ,0103 physical sciences ,Physics::Atomic and Molecular Clusters ,[CHIM]Chemical Sciences ,Physics::Atomic Physics ,Physical and Theoretical Chemistry ,010306 general physics ,Spectroscopy ,[PHYS]Physics [physics] ,Physics ,Attophysics ,021001 nanoscience & nanotechnology ,Laser ,3. Good health ,Characterization (materials science) ,Coupling (physics) ,Atomic physics ,0210 nano-technology - Abstract
International audience; We review the present state of the application of attosecond lasers in molecular physics. Following the first synthesis and characterization of attosecond laser pulses a little more than a decade ago, the first applications in molecular physics have been published only in the last few years. These have yielded new insight into the coupling of multiple electronic degrees of freedom and that of electronic and nuclear degrees of freedom on the attosecond to few-femtosecond timescale. We review these first experiments as well as theoretical work that was carried out during the same period, and sketch some future molecular applications of attosecond pump–probe spectroscopy.
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- 2013
15. Compact Raman gaz self-organizing into deep nano-trap lattice
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Chafer, Matthieu, Alharbi, Meshaal, Husakou, Anton, Debord, Benoît, Gérôme, Frédéric, Benabid, Fetah, GLOphotonics S.A.S., Photonique Fibre et Sources Cohérentes (XLIM-PHOT), XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), University of Bath [Bath], Max-Born-institut, and Max-Born-institut, Berlin
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[SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience
- Published
- 2016
16. Efficient laser production of energetic neutral beams
- Author
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Dimitri Batani, G. Birindelli, F Mollica, J. Braenzel, M. Schnuerer, B. Vauzour, Giulia Folpini, Alessandro Flacco, Victor Malka, Luca Antonelli, Sources compactes de Particules pour Lasers & Applications (SPL), Laboratoire d'optique appliquée (LOA), École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Università di Roma Tor Vergata, Università di Roma La Sapienza, Technische Universität Berlin (TU), Max-Born-institut, Max-Born-institut, Berlin, Centre d'Etudes Lasers Intenses et Applications (CELIA), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Bordeaux (UB), European Project: 284464,EC:FP7:INFRA,FP7-INFRASTRUCTURES-2011-1,LASERLAB-EUROPE(2012), Technical University of Berlin / Technische Universität Berlin (TU), and Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Materials science ,neutral beam ,Hydrogen ,chemistry.chemical_element ,7. Clean energy ,01 natural sciences ,010305 fluids & plasmas ,Ion ,law.invention ,laser-plasma interaction ,law ,[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph] ,0103 physical sciences ,Atom ,010306 general physics ,ions laser-acceleration ,[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics] ,Argon ,Energetic neutral atom ,charge transfer ,Laser ,Condensed Matter Physics ,chemistry ,Nuclear Energy and Engineering ,Atomic physics ,Nucleon ,target normal sheath acceleration ,Beam (structure) - Abstract
International audience; Laser-driven ion acceleration by intense, ultra-short, laser pulse has received increasing attention inrecent years, and the availability of much compact and versatile ions sources motivates the study oflaser-driven sources of energetic neutral atoms. We demonstrate the production of a neutral anddirectional beam of hydrogen and carbon atoms up to 200 keV per nucleon, with a peak flow of 2.7 x10(13) atom s(-1). Laser accelerated ions are neutralized in a pulsed, supersonic argon jet with tunabledensity between 1.5 x 10(17) cm(-3) and 6 x 10(18) cm(-3). The neutralization efficiency has beenmeasured by a time-of-flight detector for different argon densities. An optimum is found, for whichcomplete neutralization occurs. The neutralization rate can be explained only at high areal densities (> 1x 10(17) cm(-2)) by single electron charge transfer processes. These results suggest a new perspectivefor the study of neutral production by laser and open discussion of neutralization at a lower density.
- Published
- 2016
17. Thermal properties of high power laser bars investigated by spatially resolved thermoreflectance spectroscopy
- Author
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Dorota Pierścińska, Kamil Pierściński, Jens W. Tomm, Maciej Bugajski, Institute of Electron Technology, Institute of Electron Technology, Warsaw, Max-Born-institut, and Max-Born-institut, Berlin
- Subjects
Materials science ,FOS: Physical sciences ,law.invention ,temperature distribution ,Reliability (semiconductor) ,law ,laser bar ,Thermal ,Materials Chemistry ,Electrical and Electronic Engineering ,Spectroscopy ,Image resolution ,Condensed Matter - Materials Science ,business.industry ,PACS : 85.80.-b ,Materials Science (cond-mat.mtrl-sci) ,Surfaces and Interfaces ,Condensed Matter Physics ,Laser ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Power (physics) ,Faceting ,Modulation ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Optoelectronics ,thermoreflectance ,business - Abstract
In this work we present results of the analysis of thermal properties of high-power laser bars obtained by spatially resolved thermoreflectance (TR) spectroscopy. Thermoreflectance is a modulation technique relying on periodic facet temperature modulation induced by pulsed current supply of the laser. The periodic temperature change of the laser induces variation of the refractive index and consequently modulates probe beam reflectivity. The technique has a spatial resolution of about ~1 $\mu$m and can be used for temperature mapping over 300 $\mu$m x 300 $\mu$m area. Information obtained in these experiments provide an insight into thermal processes occurring at devices' facets and consequently lead to increased reliability and substantially longer lifetimes of such structures., Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions)
- Published
- 2007
18. XUV excitation followed by ultrafast non-adiabatic relaxation in PAH molecules as a femto-astrochemistry experiment
- Author
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Marcus Vrakking, M. C. E. Galbraith, T. Barillot, Alexander G. G. M. Tielens, Vincent Loriot, Arnaud Rouzée, A. Marciniak, Susanta Mahapatra, Chung-Hsin Yang, S. Nagaprasad Reddy, Alexander I. Kuleff, J. Klei, C. T. L. Smeenk, V. Despré, Franck Lépine, Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Max-Born-institut, Berlin, School of Chemistry, University of Hyderabad, University of Hyderabad, Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Physikalisch-Chemisches Institut [Heidelberg] (PCI), Universität Heidelberg [Heidelberg], Marciniak, A., Despré, V., Barillot, T., Rouzée, A., Galbraith, M. C. E., Klei, J., Yang, C. -H., Smeenk, C. T. L., Loriot, V., Reddy, S. Nagaprasad, Tielens, A. G. G. M., Mahapatra, S., Kuleff, A. I., Vrakking, M. J. J., and Lépine, F.
- Subjects
Genetics and Molecular Biology (all) ,Astrochemistry ,Attosecond ,General Physics and Astronomy ,Molecular physics ,Biochemistry ,Article ,General Biochemistry, Genetics and Molecular Biology ,[SPI]Engineering Sciences [physics] ,Physics and Astronomy (all) ,Physics::Atomic and Molecular Clusters ,[CHIM]Chemical Sciences ,Atomic and molecular physics ,Astrophysics::Galaxy Astrophysics ,[PHYS]Physics [physics] ,Biochemistry, Genetics and Molecular Biology (all) ,Multidisciplinary ,Relaxation (NMR) ,Chemistry (all) ,General Chemistry ,Chemical sciences ,13. Climate action ,Excited state ,Extreme ultraviolet ,Femtosecond ,Atomic physics ,Ultrashort pulse ,Excitation - Abstract
Highly excited molecular species are at play in the chemistry of interstellar media and are involved in the creation of radiation damage in a biological tissue. Recently developed ultrashort extreme ultraviolet light sources offer the high excitation energies and ultrafast time-resolution required for probing the dynamics of highly excited molecular states on femtosecond (fs) (1 fs=10−15s) and even attosecond (as) (1 as=10−18 s) timescales. Here we show that polycyclic aromatic hydrocarbons (PAHs) undergo ultrafast relaxation on a few tens of femtoseconds timescales, involving an interplay between the electronic and vibrational degrees of freedom. Our work reveals a general property of excited radical PAHs that can help to elucidate the assignment of diffuse interstellar absorption bands in astrochemistry, and provides a benchmark for the manner in which coupled electronic and nuclear dynamics determines reaction pathways in large molecules following extreme ultraviolet excitation., Extreme UV light sources allow us to study the dynamics of excited molecular stets over remarkably short timeframes. Here, the authors probe polyaromatic hydrocarbons—large organic molecules—and show their electronic excitation and subsequent ultrafast relaxation.
- Published
- 2015
19. Attosecond hole migration in benzene molecules surviving nuclear motion
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A. Marciniak, V. Despré, M. C. E. Galbraith, Arnaud Rouzée, Marc J. J. Vrakking, Franck Lépine, Alexander I. Kuleff, Vincent Loriot, Despré, V., Marciniak, A., Loriot, V., Galbraith, M. C. E., Rouzée, A., Vrakking, M. J. J., Lépine, F., Kuleff, A. I., Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Max-Born-institut, Berlin, Theoretische Chemie Universität Heidelberg, and Universität Heidelberg [Heidelberg]
- Subjects
Hydrogen ,Attosecond ,Dephasing ,ultrafast physic ,chemistry.chemical_element ,electron dynamic ,01 natural sciences ,ultrafast physics ,[SPI]Engineering Sciences [physics] ,Ionization ,Quantum mechanics ,0103 physical sciences ,XUV science ,attosecond physics ,electron dynamics ,multielectronic theory ,Materials Science (all) ,[CHIM]Chemical Sciences ,General Materials Science ,Physical and Theoretical Chemistry ,010306 general physics ,Physics ,[PHYS]Physics [physics] ,010304 chemical physics ,Electronic correlation ,Dynamics (mechanics) ,attosecond physic ,Coupling (physics) ,chemistry ,Atomic physics ,Ultrashort pulse - Abstract
International audience; Hole migration is a fascinating process driven by electron correlation, in which purely electronic dynamics occur on a very short time scale in complex ionized molecules, prior to the onset of nuclear motion. However, it is expected that due to coupling to the nuclear dynamics, these oscillations will be rapidly damped and smeared out, which makes experimental observation of the hole migration process rather difficult. In this Letter, we demonstrate that the instantaneous ionization of benzene molecules initiates an ultrafast hole migration characterized by a periodic breathing of the hole density between the carbon ring and surrounding hydrogen atoms on a subfemtosecond time scale. We show that these oscillations survive the dephasing introduced by the nuclear motion for a long enough time to allow their observation. We argue that this offers an ideal benchmark for studying the influence of hole migration on molecular reactivity.
- Published
- 2015
20. Macro-atom versus many-electron effects in ultrafast ionization of C 60
- Author
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Marcus Vrakking, P S W M Logman, O. Ghafur, G. Gademann, C. Cauchy, Christian Bordas, Y. Huismans, F. Lépine, A. Gijsbertsen, Per Johnsson, Paul-Antoine Hervieux, Eric Cormier, T. Barillot, FOM Institute for Atomic and Molecular Physics (AMOLF), Centre d'Etudes Lasers Intenses et Applications (CELIA), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Bordeaux (UB), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Max-Born-institut, Berlin, Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), VIDAL, Armelle, Chemistry and Pharmaceutical Sciences, Research and Theory in Education, and Physical Chemistry
- Subjects
Angular momentum ,[SPI] Engineering Sciences [physics] ,02 engineering and technology ,Electron ,01 natural sciences ,Spectral line ,[PHYS] Physics [physics] ,[SPI]Engineering Sciences [physics] ,Ionization ,0103 physical sciences ,Atom ,[CHIM] Chemical Sciences ,Physics::Atomic and Molecular Clusters ,Molecule ,[CHIM]Chemical Sciences ,Physics::Atomic Physics ,SDG 7 - Affordable and Clean Energy ,010306 general physics ,Physics ,[PHYS]Physics [physics] ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,Pulse (physics) ,Atomic physics ,0210 nano-technology ,Ultrashort pulse - Abstract
International audience; Ionization mechanisms of C60 molecules irradiated by a short intense 800-nm laser pulse are studied. Angle-resolved photoelectron spectra show above-threshold ionization (ATI) patterns with a low peak contrast and a remarkably smooth angular distribution. The results are interpreted by combining two theoretical models. A time-dependent Schrödinger equation (TDSE) calculation based on the B-spline method that explicitly takes into account the molecular potential mimics the single-active-electron response while a statistical model accounts for the many-electron effects. We show that the latter are responsible for the loss of contrast in the ATI peaks. The smooth angular distribution arises in the TDSE calculation as a result of the high angular momentum of the C60 ground electronic state and therefore is a manifestation of the atomic behavior of the molecule.
- Published
- 2013
21. Hydrogen atoms under magnification: direct observation of the nodal structure of Stark states
- Author
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Marc J. J. Vrakking, Samuel Cohen, Francis Robicheaux, A. Gijsbertsen, Franck Lépine, Arnaud Rouzée, Julia H. Jungmann, A. S. Stodolna, Christian Bordas, FOM Institute for Atomic and Molecular Physics (AMOLF), Max-Born-institut, Berlin, Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Ioannina), University of Ioannina, Department of Physics [Auburn], and Auburn University (AU)
- Subjects
Physics ,[PHYS]Physics [physics] ,General Physics and Astronomy ,Hydrogen atom ,Electron ,Photoionization ,Parabolic coordinates ,01 natural sciences ,010305 fluids & plasmas ,Schrödinger equation ,symbols.namesake ,[SPI]Engineering Sciences [physics] ,Electric field ,Quantum mechanics ,0103 physical sciences ,symbols ,[CHIM]Chemical Sciences ,Atomic physics ,010306 general physics ,Hamiltonian (quantum mechanics) ,Wave function - Abstract
International audience; To describe the microscopic properties of matter, quantum mechanics uses wave functions, whose structure and time dependence is governed by the Schrödinger equation. In atoms the charge distributions described by the wave function are rarely observed. The hydrogen atom is unique, since it only has one electron and, in a dc electric field, the Stark Hamiltonian is exactly separable in terms of parabolic coordinates (η, ξ, φ). As a result, the microscopic wave function along the ξ coordinate that exists in the vicinity of the atom, and the projection of the continuum wave function measured at a macroscopic distance, share the same nodal structure. In this Letter, we report photoionization microscopy experiments where this nodal structure is directly observed. The experiments provide a validation of theoretical predictions that have been made over the last three decades.
- Published
- 2013
22. Single-Size Thermometric Measurements on a Size Distribution of Neutral Fullerenes
- Author
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Marcus Vrakking, Joost M. Bakker, Y. Huismans, Ch. Bordas, C. Cauchy, Arnaud Rouzée, Britta Redlich, A.F.G. van der Meer, Franck Lépine, Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), FOM Institute for Plasma Physics Rijnhuizen, FOM Institute for Atomic and Molecular Physics (AMOLF), Max-Born-institut, Berlin, Institute for Molecules and Materials [Nijmegen], and Radboud university [Nijmegen]
- Subjects
Materials science ,Fullerene ,Infrared ,numbers: 36 ,General Physics and Astronomy ,Thermionic emission ,02 engineering and technology ,Electron ,01 natural sciences ,7. Clean energy ,[SPI]Engineering Sciences [physics] ,0103 physical sciences ,Molecule ,[CHIM]Chemical Sciences ,Redistribution (chemistry) ,FELIX ,010306 general physics ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) ,[PHYS]Physics [physics] ,Free-electron laser ,Àc ,021001 nanoscience & nanotechnology ,Àb ,Electron kinetic energy ,Atomic physics ,0210 nano-technology - Abstract
International audience; We present measurements of the velocity distribution of electrons emitted from mass-selected neutral fullerenes, performed at the intracavity free electron laser FELICE. We make use of mass-specific vibrational resonances in the infrared domain to selectively heat up one out of a distribution of several fullerene species. Efficient energy redistribution leads to decay via thermionic emission. Time-resolved electron kinetic energy distributions measured give information on the decay rate of the selected fullerene. This method is generally applicable to all neutral species that exhibit thermionic emission and provides a unique tool to study the stability of mass-selected neutral clusters and molecules that are only available as part of a size distribution.
- Published
- 2013
23. Wave Function Microscopy of Quasibound Atomic States
- Author
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A. Ollagnier, Marcus Vrakking, Francis Robicheaux, T. Barillot, M. M. Harb, Christian Bordas, Franck Lépine, Samuel Cohen, Department of Physics [Ioannina), University of Ioannina, Institut Lumière Matière [Villeurbanne] (ILM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Department of Physics [Auburn], Auburn University (AU), and Max-Born-institut, Berlin
- Subjects
Physics ,[PHYS]Physics [physics] ,32.80.Rm ,Wave packet ,General Physics and Astronomy ,numbers: 32.80.Fb ,Electron ,Photoionization ,01 natural sciences ,Resonance (particle physics) ,010305 fluids & plasmas ,[SPI]Engineering Sciences [physics] ,Ionization ,0103 physical sciences ,Atom ,Physics::Atomic and Molecular Clusters ,[CHIM]Chemical Sciences ,Physics::Atomic Physics ,Atomic physics ,010306 general physics ,Wave function ,Excitation ,32.60.+i - Abstract
International audience; In the 1980s Demkov, Kondratovich, and Ostrovsky and Kondratovich and Ostrovsky proposed an experiment based on the projection of slow electrons emitted by a photoionized atom onto a position-sensitive detector. In the case of resonant excitation, they predicted that the spatial electron distribution on the detector should represent nothing else but a magnified image of the projection of a quasibound electronic state. By exciting lithium atoms in the presence of a static electric field, we present in this Letter the first experimental photoionization wave function microscopy images where signatures of quasibound states are evident. Characteristic resonant features, such as (i) the abrupt change of the number of wave function nodes across a resonance and (ii) the broadening of the outer ring of the image (associated with tunneling ionization), are observed and interpreted via wave packet propagation simulations and recently proposed resonance tunneling mechanisms. The electron spatial distribution measured by our microscope is a direct macroscopic image of the projection of the microscopic squared modulus of the electron wave that is quasibound to the atom and constitutes the first experimental realization of the experiment proposed 30 years ago.
- Published
- 2013
24. Single-pulse ultrafast laser imprinting of axial dot arrays in bulk glasses
- Author
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S. Landon, Nicolas Huot, I. Myiamoto, Alexandre Mermillod-Blondin, Eric Audouard, Cyril Mauclair, Arkadi Rosenfeld, Ingolf V. Hertel, Razvan Stoian, Laboratoire Hubert Curien [Saint Etienne] (LHC), Institut d'Optique Graduate School (IOGS)-Université Jean Monnet [Saint-Étienne] (UJM)-Centre National de la Recherche Scientifique (CNRS), Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie (MBI), Forschungsverbund Berlin e.V. (FVB) (FVB)-Leibniz Gemeinschaft, Osaka University, Osaka 565-0871, Japan, Osaka University [Osaka], and ULTRA Laboratoire Hubert Curien and Max Born Institut Berlin
- Subjects
Materials science ,Wave propagation ,Physics::Optics ,02 engineering and technology ,01 natural sciences ,law.invention ,010309 optics ,Optics ,Lasers and laser optics : Laser materials processing ,Apodization ,Machining ,law ,0103 physical sciences ,Ultrafast optics : Femtosecond phenomena ,Wavefront ,# (140.3390) Lasers and laser optics : Laser materials processing # (320.2250) Ultrafast optics : Femtosecond phenomena # (070.7345) Fourier optics and signal processing : Wave propagation ,Borosilicate glass ,business.industry ,021001 nanoscience & nanotechnology ,Laser ,Atomic and Molecular Physics, and Optics ,[SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic ,0210 nano-technology ,business ,Phase modulation ,Ultrashort pulse ,Fourier optics and signal processing : Wave propagation - Abstract
International audience; Ultrafast laser processing of bulk transparent materials can significantly gain flexibility when the number of machining spots is increased. We present a photoinscription regime in which an array of regular dots is generated before the region of main laser focus under single-pulse exposure in fused silica and borosilicate crown glass without any external spatial phase modulation. The specific position of the dots does not rely on nonlinear propagation effects but is mainly determined by beam truncation and is explained by a Fresnel propagation formalism taking into account beam apodization and linear wavefront distortions at the air/glass interface. The photoinscription regime is employed to generate a two-dimensional array of dots in fused silica. We show that an additional phase modulation renders flexible the pattern geometry.
- Published
- 2011
25. Author Correction: Capturing electron-driven chiral dynamics in UV-excited molecules.
- Author
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Wanie V, Bloch E, Månsson EP, Colaizzi L, Ryabchuk S, Saraswathula K, Ordonez AF, Ayuso D, Smirnova O, Trabattoni A, Blanchet V, Ben Amor N, Heitz MC, Mairesse Y, Pons B, and Calegari F
- Published
- 2024
- Full Text
- View/download PDF
26. Py3BR: A software for computing atomic three-body recombination rates.
- Author
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Koots R, Wang Y, Mirahmadi M, and Pérez-Ríos J
- Abstract
The three-body recombination reaction, or ternary association, is a termolecular reaction leading to a molecule after a three-body encounter that plays a vital role in many relevant scenarios in chemical physics. Here, we introduce the Python 3-Body Recombination program, which is dedicated to the computation of atomic three-body recombination rate coefficients. The software is based on a classical trajectory approach in hyperspherical coordinates after mapping the three-body problem as a single particle in a higher-dimensional space. This theoretical approach is fully general and applicable to any ion-atom-atom or atom-atom-atom three-body process. The predictive power of the methodology has been tested in several different experimental scenarios, reaching a good description of every system. The code structure is presented alongside examples and tests to ensure the software's capacity. In addition, the performance of the software after parallelization is shown., (© 2024 Wiley Periodicals LLC.)
- Published
- 2024
- Full Text
- View/download PDF
27. Capturing electron-driven chiral dynamics in UV-excited molecules.
- Author
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Wanie V, Bloch E, Månsson EP, Colaizzi L, Ryabchuk S, Saraswathula K, Ordonez AF, Ayuso D, Smirnova O, Trabattoni A, Blanchet V, Ben Amor N, Heitz MC, Mairesse Y, Pons B, and Calegari F
- Abstract
Chiral molecules, used in applications such as enantioselective photocatalysis
1 , circularly polarized light detection2 and emission3 and molecular switches4,5 , exist in two geometrical configurations that are non-superimposable mirror images of each other. These so-called (R) and (S) enantiomers exhibit different physical and chemical properties when interacting with other chiral entities. Attosecond technology might enable influence over such interactions, given that it can probe and even direct electron motion within molecules on the intrinsic electronic timescale6 and thereby control reactivity7-9 . Electron currents in photoexcited chiral molecules have indeed been predicted to enable enantiosensitive molecular orientation10 , but electron-driven chiral dynamics in neutral molecules have not yet been demonstrated owing to the lack of ultrashort, non-ionizing and perturbative light pulses. Here we use time-resolved photoelectron circular dichroism (TR-PECD)11-15 with an unprecedented temporal resolution of 2.9 fs to map the coherent electronic motion initiated by ultraviolet (UV) excitation of neutral chiral molecules. We find that electronic beatings between Rydberg states lead to periodic modulations of the chiroptical response on the few-femtosecond timescale, showing a sign inversion in less than 10 fs. Calculations validate this and also confirm that the combination of the photoinduced chiral current with a circularly polarized probe pulse realizes an enantioselective filter of molecular orientations following photoionization. We anticipate that our approach will enable further investigations of ultrafast electron dynamics in chiral systems and reveal a route towards enantiosensitive charge-directed reactivity., (© 2024. The Author(s).)- Published
- 2024
- Full Text
- View/download PDF
28. Quantum-mechanical effects in photoluminescence from thin crystalline gold films.
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Bowman AR, Rodríguez Echarri A, Kiani F, Iyikanat F, Tsoulos TV, Cox JD, Sundararaman R, García de Abajo FJ, and Tagliabue G
- Abstract
Luminescence constitutes a unique source of insight into hot carrier processes in metals, including those in plasmonic nanostructures used for sensing and energy applications. However, being weak in nature, metal luminescence remains poorly understood, its microscopic origin strongly debated, and its potential for unraveling nanoscale carrier dynamics largely unexploited. Here, we reveal quantum-mechanical effects in the luminescence emanating from thin monocrystalline gold flakes. Specifically, we present experimental evidence, supported by first-principles simulations, to demonstrate its photoluminescence origin (i.e., radiative emission from electron/hole recombination) when exciting in the interband regime. Our model allows us to identify changes to the measured gold luminescence due to quantum-mechanical effects as the gold film thickness is reduced. Excitingly, such effects are observable in the luminescence signal from flakes up to 40 nm in thickness, associated with the out-of-plane discreteness of the electronic band structure near the Fermi level. We qualitatively reproduce the observations with first-principles modeling, thus establishing a unified description of luminescence in gold monocrystalline flakes and enabling its widespread application as a probe of carrier dynamics and light-matter interactions in this material. Our study paves the way for future explorations of hot carriers and charge-transfer dynamics in a multitude of material systems., (© 2024. The Author(s).)
- Published
- 2024
- Full Text
- View/download PDF
29. Valleytronics in bulk MoS 2 with a topologic optical field.
- Author
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Tyulnev I, Jiménez-Galán Á, Poborska J, Vamos L, Russell PSJ, Tani F, Smirnova O, Ivanov M, Silva REF, and Biegert J
- Abstract
The valley degree of freedom
1-4 of electrons in materials promises routes towards energy-efficient information storage with enticing prospects for quantum information processing5-7 . Current challenges in utilizing valley polarization are symmetry conditions that require monolayer structures8,9 or specific material engineering10-13 , non-resonant optical control to avoid energy dissipation and the ability to switch valley polarization at optical speed. We demonstrate all-optical and non-resonant control over valley polarization using bulk MoS2, a centrosymmetric material without Berry curvature at the valleys. Our universal method utilizes spin angular momentum-shaped trefoil optical control pulses14,15 to switch the material's electronic topology and induce valley polarization by transiently breaking time and space inversion symmetry16 through a simple phase rotation. We confirm valley polarization through the transient generation of the second harmonic of a non-collinear optical probe pulse, depending on the trefoil phase rotation. The investigation shows that direct optical control over the valley degree of freedom is not limited to monolayer structures. Indeed, such control is possible for systems with an arbitrary number of layers and for bulk materials. Non-resonant valley control is universal and, at optical speeds, unlocks the possibility of engineering efficient multimaterial valleytronic devices operating on quantum coherent timescales., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)- Published
- 2024
- Full Text
- View/download PDF
30. Ultrafast electronic relaxation pathways of the molecular photoswitch quadricyclane.
- Author
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Borne KD, Cooper JC, Ashfold MNR, Bachmann J, Bhattacharyya S, Boll R, Bonanomi M, Bosch M, Callegari C, Centurion M, Coreno M, Curchod BFE, Danailov MB, Demidovich A, Di Fraia M, Erk B, Faccialà D, Feifel R, Forbes RJG, Hansen CS, Holland DMP, Ingle RA, Lindh R, Ma L, McGhee HG, Muvva SB, Nunes JPF, Odate A, Pathak S, Plekan O, Prince KC, Rebernik P, Rouzée A, Rudenko A, Simoncig A, Squibb RJ, Venkatachalam AS, Vozzi C, Weber PM, Kirrander A, and Rolles D
- Abstract
The light-induced ultrafast switching between molecular isomers norbornadiene and quadricyclane can reversibly store and release a substantial amount of chemical energy. Prior work observed signatures of ultrafast molecular dynamics in both isomers upon ultraviolet excitation but could not follow the electronic relaxation all the way back to the ground state experimentally. Here we study the electronic relaxation of quadricyclane after exciting in the ultraviolet (201 nanometres) using time-resolved gas-phase extreme ultraviolet photoelectron spectroscopy combined with non-adiabatic molecular dynamics simulations. We identify two competing pathways by which electronically excited quadricyclane molecules relax to the electronic ground state. The fast pathway (<100 femtoseconds) is distinguished by effective coupling to valence electronic states, while the slow pathway involves initial motions across Rydberg states and takes several hundred femtoseconds. Both pathways facilitate interconversion between the two isomers, albeit on different timescales, and we predict that the branching ratio of norbornadiene/quadricyclane products immediately after returning to the electronic ground state is approximately 3:2., (© 2024. The Author(s).)
- Published
- 2024
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31. Observation of interband Berry phase in laser-driven crystals.
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Uzan-Narovlansky AJ, Faeyrman L, Brown GG, Shames S, Narovlansky V, Xiao J, Arusi-Parpar T, Kneller O, Bruner BD, Smirnova O, Silva REF, Yan B, Jiménez-Galán Á, Ivanov M, and Dudovich N
- Abstract
Ever since its discovery
1 , the notion of the Berry phase has permeated all branches of physics and plays an important part in a variety of quantum phenomena2 . However, so far all its realizations have been based on a continuous evolution of the quantum state, following a cyclic path. Here we introduce and demonstrate a conceptually new manifestation of the Berry phase in light-driven crystals, in which the electronic wavefunction accumulates a geometric phase during a discrete evolution between different bands, while preserving the coherence of the process. We experimentally reveal this phase by using a strong laser field to engineer an internal interferometer, induced during less than one cycle of the driving field, which maps the phase onto the emission of higher-order harmonics. Our work provides an opportunity for the study of geometric phases, leading to a variety of observations in light-driven topological phenomena and attosecond solid-state physics., (© 2024. The Author(s).)- Published
- 2024
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32. Finding the semantic similarity in single-particle diffraction images using self-supervised contrastive projection learning.
- Author
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Zimmermann J, Beguet F, Guthruf D, Langbehn B, and Rupp D
- Abstract
Single-shot coherent diffraction imaging of isolated nanosized particles has seen remarkable success in recent years, yielding in-situ measurements with ultra-high spatial and temporal resolution. The progress of high-repetition-rate sources for intense X-ray pulses has further enabled recording datasets containing millions of diffraction images, which are needed for the structure determination of specimens with greater structural variety and dynamic experiments. The size of the datasets, however, represents a monumental problem for their analysis. Here, we present an automatized approach for finding semantic similarities in coherent diffraction images without relying on human expert labeling. By introducing the concept of projection learning, we extend self-supervised contrastive learning to the context of coherent diffraction imaging and achieve a dimensionality reduction producing semantically meaningful embeddings that align with physical intuition. The method yields substantial improvements compared to previous approaches, paving the way toward real-time and large-scale analysis of coherent diffraction experiments at X-ray free-electron lasers., Competing Interests: Competing interestsThe authors declare no competing financial or non-financial interests., (© The Author(s) 2023, corrected publication 2023.)
- Published
- 2023
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33. Nonequilibrium sub-10 nm spin-wave soliton formation in FePt nanoparticles.
- Author
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Turenne D, Yaroslavtsev A, Wang X, Unikandanuni V, Vaskivskyi I, Schneider M, Jal E, Carley R, Mercurio G, Gort R, Agarwal N, Van Kuiken B, Mercadier L, Schlappa J, Le Guyader L, Gerasimova N, Teichmann M, Lomidze D, Castoldi A, Potorochin D, Mukkattukavil D, Brock J, Zhou Hagström N, Reid AH, Shen X, Wang XJ, Maldonado P, Kvashnin Y, Carva K, Wang J, Takahashi YK, Fullerton EE, Eisebitt S, Oppeneer PM, Molodtsov S, Scherz A, Bonetti S, Iacocca E, and Dürr HA
- Abstract
Magnetic nanoparticles such as FePt in the L1
0 phase are the bedrock of our current data storage technology. As the grains become smaller to keep up with technological demands, the superparamagnetic limit calls for materials with higher magnetocrystalline anisotropy. This, in turn, reduces the magnetic exchange length to just a few nanometers, enabling magnetic structures to be induced within the nanoparticles. Here, we describe the existence of spin-wave solitons, dynamic localized bound states of spin-wave excitations, in FePt nanoparticles. We show with time-resolved x-ray diffraction and micromagnetic modeling that spin-wave solitons of sub-10 nm sizes form out of the demagnetized state following femtosecond laser excitation. The measured soliton spin precession frequency of 0.1 THz positions this system as a platform to develop novel miniature devices.- Published
- 2022
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34. Enantio-sensitive unidirectional light bending.
- Author
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Ayuso D, Ordonez AF, Decleva P, Ivanov M, and Smirnova O
- Abstract
Structured light, which exhibits nontrivial intensity, phase, and polarization patterns in space, has key applications ranging from imaging and 3D micromanipulation to classical and quantum communication. However, to date, its application to molecular chirality has been limited by the weakness of magnetic interactions. Here we structure light's local handedness in space to introduce and realize an enantio-sensitive interferometer for efficient chiral recognition without magnetic interactions, which can be seen as an enantio-sensitive version of Young's double slit experiment. Upon interaction with isotropic chiral media, such chirality-structured light effectively creates chiral emitters of opposite handedness, located at different positions in space. We show that if the distribution of light's handedness breaks left-right symmetry, the interference of these chiral emitters leads to unidirectional bending of the emitted light, in opposite directions in media of opposite handedness, even if the number of the left-handed and right-handed emitters excited in the medium is exactly the same. Our work introduces the concepts of polarization of chirality and chirality-polarized light, exposes the immense potential of sculpting light's local chirality, and offers novel opportunities for efficient chiral discrimination, enantio-sensitive optical molecular fingerprinting and imaging on ultrafast time scales.
- Published
- 2021
- Full Text
- View/download PDF
35. Elliptically polarized high-harmonic radiation for production of isolated attosecond pulses.
- Author
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Bengs U and Zhavoronkov N
- Abstract
Circularly polarized attosecond pulses are powerful tool to study chiral light-matter interaction via chiral electron dynamics. However, access to isolated circularly polarized attosecond pulses enabling straightforward interpretation of measurements, still remains a challenge. In this work, we experimentally demonstrate the generation of highly elliptically polarized high-harmonics in a two-color, bi-circular, collinear laser field. The intensity and shape of the combined few-cycle driving radiation is optimized to produce a broadband continuum with enhanced spectral chirality in the range of 15-55 eV supporting the generation of isolated attosecond pulses with duration down to 150 as. We apply spectrally resolved polarimetry to determine the full Stokes vector of different spectral components of the continuum, yielding a homogenous helicity distribution with ellipticity in the range of 0.8-0.95 and a negligible unpolarized content.
- Published
- 2021
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36. Topological protection versus degree of entanglement of two-photon light in photonic topological insulators.
- Author
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Tschernig K, Jimenez-Galán Á, Christodoulides DN, Ivanov M, Busch K, Bandres MA, and Perez-Leija A
- Abstract
Topological insulators combine insulating properties in the bulk with scattering-free transport along edges, supporting dissipationless unidirectional energy and information flow even in the presence of defects and disorder. The feasibility of engineering quantum Hamiltonians with photonic tools, combined with the availability of entangled photons, raises the intriguing possibility of employing topologically protected entangled states in optical quantum computing and information processing. However, while two-photon states built as a product of two topologically protected single-photon states inherit full protection from their single-photon "parents", a high degree of non-separability may lead to rapid deterioration of the two-photon states after propagation through disorder. In this work, we identify physical mechanisms which contribute to the vulnerability of entangled states in topological photonic lattices. Further, we show that in order to maximize entanglement without sacrificing topological protection, the joint spectral correlation map of two-photon states must fit inside a well-defined topological window of protection.
- Published
- 2021
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37. Observation of fluctuation-mediated picosecond nucleation of a topological phase.
- Author
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Büttner F, Pfau B, Böttcher M, Schneider M, Mercurio G, Günther CM, Hessing P, Klose C, Wittmann A, Gerlinger K, Kern LM, Strüber C, von Korff Schmising C, Fuchs J, Engel D, Churikova A, Huang S, Suzuki D, Lemesh I, Huang M, Caretta L, Weder D, Gaida JH, Möller M, Harvey TR, Zayko S, Bagschik K, Carley R, Mercadier L, Schlappa J, Yaroslavtsev A, Le Guyarder L, Gerasimova N, Scherz A, Deiter C, Gort R, Hickin D, Zhu J, Turcato M, Lomidze D, Erdinger F, Castoldi A, Maffessanti S, Porro M, Samartsev A, Sinova J, Ropers C, Mentink JH, Dupé B, Beach GSD, and Eisebitt S
- Abstract
Topological states of matter exhibit fascinating physics combined with an intrinsic stability. A key challenge is the fast creation of topological phases, which requires massive reorientation of charge or spin degrees of freedom. Here we report the picosecond emergence of an extended topological phase that comprises many magnetic skyrmions. The nucleation of this phase, followed in real time via single-shot soft X-ray scattering after infrared laser excitation, is mediated by a transient topological fluctuation state. This state is enabled by the presence of a time-reversal symmetry-breaking perpendicular magnetic field and exists for less than 300 ps. Atomistic simulations indicate that the fluctuation state largely reduces the topological energy barrier and thereby enables the observed rapid and homogeneous nucleation of the skyrmion phase. These observations provide fundamental insights into the nature of topological phase transitions, and suggest a path towards ultrafast topological switching in a wide variety of materials through intermediate fluctuating states.
- Published
- 2021
- Full Text
- View/download PDF
38. Tracking the ultraviolet-induced photochemistry of thiophenone during and after ultrafast ring opening.
- Author
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Pathak S, Ibele LM, Boll R, Callegari C, Demidovich A, Erk B, Feifel R, Forbes R, Di Fraia M, Giannessi L, Hansen CS, Holland DMP, Ingle RA, Mason R, Plekan O, Prince KC, Rouzée A, Squibb RJ, Tross J, Ashfold MNR, Curchod BFE, and Rolles D
- Abstract
Photoinduced isomerization reactions lie at the heart of many chemical processes in nature. The mechanisms of such reactions are determined by a delicate interplay of coupled electronic and nuclear dynamics occurring on the femtosecond scale, followed by the slower redistribution of energy into different vibrational degrees of freedom. Here we apply time-resolved photoelectron spectroscopy with a seeded extreme ultraviolet free-electron laser to trace the ultrafast ring opening of gas-phase thiophenone molecules following ultraviolet photoexcitation. When combined with ab initio electronic structure and molecular dynamics calculations of the excited- and ground-state molecules, the results provide insights into both the electronic and nuclear dynamics of this fundamental class of reactions. The initial ring opening and non-adiabatic coupling to the electronic ground state are shown to be driven by ballistic S-C bond extension and to be complete within 350 fs. Theory and experiment also enable visualization of the rich ground-state dynamics that involve the formation of, and interconversion between, ring-opened isomers and the cyclic structure, as well as fragmentation over much longer timescales.
- Published
- 2020
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39. Photo-ionization and fragmentation of Sc 3 N@C 80 following excitation above the Sc K-edge.
- Author
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Obaid R, Schnorr K, Wolf TJA, Takanashi T, Kling NG, Kooser K, Nagaya K, Wada SI, Fang L, Augustin S, You D, Campbell EEB, Fukuzawa H, Schulz CP, Ueda K, Lablanquie P, Pfeifer T, Kukk E, and Berrah N
- Abstract
We have investigated the ionization and fragmentation of a metallo-endohedral fullerene, Sc
3 N@C80 , using ultrashort (10 fs) x-ray pulses. Following selective ionization of a Sc (1s) electron (hν = 4.55 keV), an Auger cascade leads predominantly to either a vibrationally cold multiply charged parent molecule or multifragmentation of the carbon cage following a phase transition. In contrast to previous studies, no intermediate regime of C2 evaporation from the carbon cage is observed. A time-delayed, hard x-ray pulse (hν = 5.0 keV) was used to attempt to probe the electron transfer dynamics between the encapsulated Sc species and the carbon cage. A small but significant change in the intensity of Sc-containing fragment ions and coincidence counts for a delay of 100 fs compared to 0 fs, as well as an increase in the yield of small carbon fragment ions, may be indicative of incomplete charge transfer from the carbon cage on the sub-100 fs time scale.- Published
- 2019
- Full Text
- View/download PDF
40. Extreme-ultraviolet refractive optics.
- Author
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Drescher L, Kornilov O, Witting T, Reitsma G, Monserud N, Rouzée A, Mikosch J, Vrakking MJJ, and Schütte B
- Abstract
Refraction is a well-known optical phenomenon that alters the direction of light waves propagating through matter. Microscopes, lenses and prisms based on refraction are indispensable tools for controlling light beams at visible, infrared, ultraviolet and X-ray wavelengths
1 . In the past few decades, a range of extreme-ultraviolet and soft-X-ray sources has been developed in laboratory environments2-4 and at large-scale facilities5,6 . But the strong absorption of extreme-ultraviolet radiation in matter hinders the development of refractive lenses and prisms in this spectral region, for which reflective mirrors and diffractive Fresnel zone plates7 are instead used for focusing. Here we demonstrate control over the refraction of extreme-ultraviolet radiation by using a gas jet with a density gradient across the profile of the extreme-ultraviolet beam. We produce a gas-phase prism that leads to a frequency-dependent deflection of the beam. The strong deflection near to atomic resonances is further used to develop a deformable refractive lens for extreme-ultraviolet radiation, with low absorption and a focal length that can be tuned by varying the gas pressure. Our results open up a route towards the transfer of refraction-based techniques, which are well established in other spectral regions, to the extreme-ultraviolet domain.- Published
- 2018
- Full Text
- View/download PDF
41. Fast current-driven domain walls and small skyrmions in a compensated ferrimagnet.
- Author
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Caretta L, Mann M, Büttner F, Ueda K, Pfau B, Günther CM, Hessing P, Churikova A, Klose C, Schneider M, Engel D, Marcus C, Bono D, Bagschik K, Eisebitt S, and Beach GSD
- Abstract
Spintronics is a research field that aims to understand and control spins on the nanoscale and should enable next-generation data storage and manipulation. One technological and scientific key challenge is to stabilize small spin textures and to move them efficiently with high velocities. For a long time, research focused on ferromagnetic materials, but ferromagnets show fundamental limits for speed and size. Here, we circumvent these limits using compensated ferrimagnets. Using ferrimagnetic Pt/Gd
44 Co56 /TaOx films with a sizeable Dzyaloshinskii-Moriya interaction, we realize a current-driven domain wall motion with a speed of 1.3 km s-1 near the angular momentum compensation temperature (TA ) and room-temperature-stable skyrmions with minimum diameters close to 10 nm near the magnetic compensation temperature (TM ). Both the size and dynamics of the ferrimagnet are in excellent agreement with a simplified effective ferromagnet theory. Our work shows that high-speed, high-density spintronics devices based on current-driven spin textures can be realized using materials in which TA and TM are close together.- Published
- 2018
- Full Text
- View/download PDF
42. In situ single-shot diffractive fluence mapping for X-ray free-electron laser pulses.
- Author
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Schneider M, Günther CM, Pfau B, Capotondi F, Manfredda M, Zangrando M, Mahne N, Raimondi L, Pedersoli E, Naumenko D, and Eisebitt S
- Subjects
- Circular Dichroism, Cobalt, Platinum, X-Rays, Electrons, Lasers, Silicon Compounds, Ultraviolet Rays
- Abstract
Free-electron lasers (FELs) in the extreme ultraviolet (XUV) and X-ray regime opened up the possibility for experiments at high power densities, in particular allowing for fluence-dependent absorption and scattering experiments to reveal non-linear light-matter interactions at ever shorter wavelengths. Findings of such non-linear effects are met with tremendous interest, but prove difficult to understand and model due to the inherent shot-to-shot fluctuations in photon intensity and the often structured, non-Gaussian spatial intensity profile of a focused FEL beam. Presently, the focused beam is characterized and optimized separately from the actual experiment. Here, we present the simultaneous measurement of XUV diffraction signals from solid samples in tandem with the corresponding single-shot spatial fluence distribution on the actual sample. Our in situ characterization scheme enables direct monitoring of the sample illumination, providing a basis to optimize and quantitatively understand FEL experiments.
- Published
- 2018
- Full Text
- View/download PDF
43. Generating circularly polarized radiation in the extreme ultraviolet spectral range at the free-electron laser FLASH.
- Author
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von Korff Schmising C, Weder D, Noll T, Pfau B, Hennecke M, Strüber C, Radu I, Schneider M, Staeck S, Günther CM, Lüning J, Merhe AED, Buck J, Hartmann G, Viefhaus J, Treusch R, and Eisebitt S
- Abstract
A new device for polarization control at the free electron laser facility FLASH1 at DESY has been commissioned for user operation. The polarizer is based on phase retardation upon reflection off metallic mirrors. Its performance is characterized in three independent measurements and confirms the theoretical predictions of efficient and broadband generation of circularly polarized radiation in the extreme ultraviolet spectral range from 35 eV to 90 eV. The degree of circular polarization reaches up to 90% while maintaining high total transmission values exceeding 30%. The simple design of the device allows straightforward alignment for user operation and rapid switching between left and right circularly polarized radiation.
- Published
- 2017
- Full Text
- View/download PDF
44. Femtosecond laser excitation drives ferromagnetic gadolinium out of magnetic equilibrium.
- Author
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Carley R, Döbrich K, Frietsch B, Gahl C, Teichmann M, Schwarzkopf O, Wernet P, and Weinelt M
- Abstract
The temporal evolution of the exchange-split Δ(2)-like Σ valence bands of the 4f-ferromagnet gadolinium after femtosecond laser excitation has been studied using angle-resolved photoelectron spectroscopy based on high-order harmonic generation. The ultrafast drop of the exchange splitting reflects the magnetic response seen in femtosecond magnetic dichroism experiments. However, while the minority valence band reacts immediately, the response of the majority counterpart is delayed by 1 picosecond and is only half as fast. These findings demonstrate that laser excitation drives the valence band structure out of magnetic equilibrium.
- Published
- 2012
- Full Text
- View/download PDF
45. Quasimonoenergetic deuteron bursts produced by ultraintense laser pulses.
- Author
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Ter-Avetisyan S, Schnürer M, Nickles PV, Kalashnikov M, Risse E, Sokollik T, Sandner W, Andreev A, and Tikhonchuk V
- Abstract
We report on the generation and laser acceleration of bunches of energetic deuterons with a small energy spread at about 2 MeV. This quasimonoenergetic peak within the ion energy spectrum was observed when heavy-water microdroplets were irradiated with ultrashort laser pulses of about 40 fs duration and high (10(-8)) temporal contrast, at an intensity of 10(19) W/cm(2). The results can be explained by a simple physical model related to spatial separation of two ion species within a finite-volume target. The production of quasimonoenergetic ions is a long-standing goal in laser-particle acceleration; it could have diverse applications such as in medicine or in the development of future compact ion accelerators.
- Published
- 2006
- Full Text
- View/download PDF
46. Spin-dependent electron dynamics in front of a ferromagnetic surface.
- Author
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Schmidt AB, Pickel M, Wiemhöfer M, Donath M, and Weinelt M
- Abstract
Exchange splitting and dynamics of image-potential states in front of a 3 monolayer iron film on Cu(100) have been studied with time-, energy-, and spin-resolved bichromatic two-photon photoemission. For the first image-potential state n=1 we observe an exchange splitting of 56 +/- 10 meV and spin-dependent lifetimes of 16 +/- 2 fs for majority-spin and of 11 +/- 2 fs for minority-spin electrons, respectively. The time-resolved studies of both the population and the linewidth of image-potential states manifest that at the magnetic surface not only inelastic but also quasielastic scattering processes are spin dependent.
- Published
- 2005
- Full Text
- View/download PDF
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