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  <doc>
    <id>1698</id>
    <completedYear>2023</completedYear>
    <publishedYear/>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume>25</volume>
    <type>article</type>
    <publisherName>Institute of Physics Publishing (IOP)</publisherName>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>1</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Electron correlation dynamics in atomic Kr excited by XUV pulses and controlled by NIR laser pulses of variable intensity</title>
    <abstract language="eng">We have investigated the possibility to track and control correlation dynamics of valence electrons in krypton (Kr) initiated by the absorption of one extreme ultraviolet (XUV) photon. In this investigation, pump-probe experiments have been performed where monochromatized single high-harmonics at photon energies 29.6, 32.8, and 35.9 eV have been used as pump to populate different intermediate excited states. A temporally delayed near-infrared (NIR) pulse probes the population of various decay channels via the detection of Kr²⁺ ion yields and its transient profiles. We observe that by varying the NIR pulse intensity within a range from 0.3 x 10¹³ to 2.6 x 10¹³ W cm⁻², the shape of the Kr²+ transient profile changes significantly. We show that by varying the intensity of the NIR pulse, it is possible—(i) to control the ratio between sequential and non-sequential double ionization of Kr; (ii) to selectively probe quantum beating oscillations between Kr+* satellite states that are coherently excited within the bandwidth of the XUV pulse; and (iii) to specifically probe the relaxation dynamics of doubly excited (Kr**) decay channels. Our studies show that the contribution of different ionization and decay channels (i)–(iii) can be altered by the NIR pulse intensity, thus demonstrating an efficient way to control the ionization dynamics in rare gas atoms.</abstract>
    <parentTitle language="eng">New Journal of Physics</parentTitle>
    <identifier type="urn">urn:nbn:de:kobv:526-opus4-16987</identifier>
    <enrichment key="opus.import.data">@articleRoos_2023, doi = 10.1088/1367-2630/acb567, url = https://dx.doi.org/10.1088/1367-2630/acb567, year = 2023, month = feb, publisher = IOP Publishing, volume = 25, number = 1, pages = 013038, author = Andreas H Roos and Ziaul Hoque and Eva Klimešová and Ltaief Ben Ltaief and Cristian Medina and Matej Jurkovič and Martin Albrecht and Ondřej Finke and Ondřej Hort and Jaroslav Nejdl and Marcel Mudrich and Jakob Andreasson and Maria Krikunova, title = Electron correlation dynamics in atomic Kr excited by XUV pulses and controlled by NIR laser pulses of variable intensity, journal = New Journal of Physics, abstract = We have investigated the possibility to track and control correlation dynamics of valence electrons in krypton (Kr) initiated by the absorption of one extreme ultraviolet (XUV) photon. In this investigation, pump-probe experiments have been performed where monochromatized single high-harmonics at photon energies 29.6, 32.8, and 35.9 eV have been used as pump to populate different intermediate excited states. A temporally delayed near-infrared (NIR) pulse probes the population of various decay channels via the detection of Kr2+ ion yields and its transient profiles. We observe that by varying the NIR pulse intensity within a range from to W cm−2, the shape of the Kr2+ transient profile changes significantly. We show that by varying the intensity of the NIR pulse, it is possible—(i) to control the ratio between sequential and non-sequential double ionization of Kr; (ii) to selectively probe quantum beating oscillations between Kr satellite states that are coherently excited within the bandwidth of the XUV pulse; and (iii) to specifically probe the relaxation dynamics of doubly excited (Kr) decay channels. Our studies show that the contribution of different ionization and decay channels (i)–(iii) can be altered by the NIR pulse intensity, thus demonstrating an efficient way to control the ionization dynamics in rare gas atoms.</enrichment>
    <enrichment key="opus.import.dataHash">md5:a6a23ee17ffa425b1f1a7b458f9210df</enrichment>
    <enrichment key="opus.import.date">2023-02-03T09:18:45+00:00</enrichment>
    <enrichment key="opus.import.file">/tmp/phpaLFIdo</enrichment>
    <enrichment key="opus.import.format">bibtex</enrichment>
    <enrichment key="opus.import.id">63dcd175082ef8.49479788</enrichment>
    <enrichment key="DOI_VoR">https://doi.org/10.1088/1367-2630/acb567</enrichment>
    <enrichment key="SourceTitle">Roos, A. H., Hoque, Z., Klimešová, E., Ben Ltaief, L., Medina, C., Jurkovič, M., … Krikunova, M. (2023). Electron correlation dynamics in atomic Kr excited by XUV pulses and controlled by NIR laser pulses of variable intensity. New Journal of Physics, 25, 013038. doi:10.1088/1367-2630/acb567</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">true</enrichment>
    <licence>Creative Commons - CC BY - Namensnennung 4.0 International</licence>
    <author>Andreas Hult Roos</author>
    <author>Ziaul Hoque</author>
    <author>Eva Klimešová</author>
    <author>Ltaief Ben Ltaief</author>
    <author>Cristian Medina</author>
    <author>Matej Jurkovič</author>
    <author>Martin Albrecht</author>
    <author>Ondřej Finke</author>
    <author>Ondřej Hort</author>
    <author>Jaroslav Nejdl</author>
    <author>Marcel Mudrich</author>
    <author>Jakob Andreasson</author>
    <author>Maria Krikunova</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>electron correlation</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>control ionization dynamics</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>krypton satellite states</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>XUV/NIR pump-probe</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>HHG</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>quantum beating oscillation</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>doubly excited states</value>
    </subject>
    <collection role="ddc" number="621">Angewandte Physik</collection>
    <collection role="institutes" number="">Fachbereich Ingenieur- und Naturwissenschaften</collection>
    <collection role="open_access" number="">open_access</collection>
    <collection role="green_open_access" number="1">Gold Open Access</collection>
    <thesisPublisher>Technische Hochschule Wildau</thesisPublisher>
    <file>https://opus4.kobv.de/opus4-th-wildau/files/1698/Roos_2023_New_J._Phys._25_013038.pdf</file>
  </doc>
  <doc>
    <id>1846</id>
    <completedYear>2024</completedYear>
    <publishedYear/>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume>7</volume>
    <type>article</type>
    <publisherName>Nature Publishing Group</publisherName>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>1</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Bright continuously tunable vacuum ultraviolet source for ultrafast spectroscopy</title>
    <abstract language="eng">Ultrafast electron dynamics drive phenomena such as photochemical reactions, catalysis, and light harvesting. To capture such dynamics in real-time, femtosecond to attosecond light sources are extensively used. However, an exact match between the excitation photon energy and a characteristic resonance is crucial. High-harmonic generation sources are advantageous in terms of pulse duration but limited in spectral tunability in the vacuum ultraviolet range. Here, we present a monochromatic femtosecond source continuously tunable around 21eV photon energy utilizing the second harmonic of an optical parametric chirped pulse amplification laser system to drive high-harmonic generation. The unique tunability of the source is verified in an experiment probing the interatomic Coulombic decay in doped He nanodroplets across the He absorption bands. Moreover, we achieved intensities sufficient for driving collective processes in multiply excited helium nanodroplets, which have been previously observed only at free electron lasers.</abstract>
    <parentTitle language="eng">Communications Physics</parentTitle>
    <identifier type="issn">2399-3650</identifier>
    <identifier type="urn">urn:nbn:de:kobv:526-opus4-18462</identifier>
    <enrichment key="opus.import.date">2024-01-15T10:02:06+00:00</enrichment>
    <enrichment key="opus.source">sword</enrichment>
    <enrichment key="opus.import.user">sword</enrichment>
    <enrichment key="DOI_VoR">https://doi.org/10.1038/s42005-023-01513-5</enrichment>
    <enrichment key="SourceTitle">Jurkovičová, L., Ben Ltaief, L., Hult Roos, A. et al. Bright continuously tunable vacuum ultraviolet source for ultrafast spectroscopy. Commun Phys 7, 26 (2024). https://doi.org/10.1038/s42005-023-01513-5</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">true</enrichment>
    <licence>Creative Commons - CC BY - Namensnennung 4.0 International</licence>
    <author>Lucie Jurkovičová</author>
    <author>Ltaief Ben Ltaief</author>
    <author>Andreas Hult Roos</author>
    <author>Ondřej Hort</author>
    <author>Ondřej Finke</author>
    <author>Martin Albrecht</author>
    <author>Ziaul Hoque</author>
    <author>Eva Klimešová</author>
    <author>Akgash Sundaralingam</author>
    <author>Roman Antipenkov</author>
    <author>Annika Grenfell</author>
    <author>Alexandr Špaček</author>
    <author>Wojciech Szuba</author>
    <author>Maria Krikunova</author>
    <author>Marcel Mudrich</author>
    <author>Jaroslav Nejdl</author>
    <author>Jakob Andreasson</author>
    <collection role="ddc" number="621">Angewandte Physik</collection>
    <collection role="institutes" number="">Fachbereich Ingenieur- und Naturwissenschaften</collection>
    <collection role="open_access" number="">open_access</collection>
    <collection role="Import" number="import">Import</collection>
    <collection role="green_open_access" number="1">Gold Open Access</collection>
    <thesisPublisher>Technische Hochschule Wildau</thesisPublisher>
    <file>https://opus4.kobv.de/opus4-th-wildau/files/1846/s42005-023-01513-5.pdf</file>
  </doc>
  <doc>
    <id>1770</id>
    <completedYear>2023</completedYear>
    <publishedYear/>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume>25</volume>
    <type>article</type>
    <publisherName>Institute of Physics (IOP)</publisherName>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>1</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Long-lasting XUV activation of helium nanodroplets for avalanche ionization</title>
    <abstract language="eng">We study the dynamics of avalanche ionization of pure helium nanodroplets activated by a weak extreme-ultraviolet (XUV) pulse and driven by an intense near-infrared (NIR) pulse. In addition to a transient enhancement of ignition of a nanoplasma at short delay times ${\sim}200$ fs, long-term activation of the nanodroplets lasting up to a few nanoseconds is observed. Molecular dynamics simulations suggest that the short-term activation is caused by the injection of seed electrons into the droplets by XUV photoemission. Long-term activation appears due to electrons remaining loosely bound to photoions which form stable 'snowball' structures in the droplets. Thus, we show that XUV irradiation can induce long-lasting changes of the strong-field optical properties of nanoparticles, potentially opening new routes to controlling avalanche-ionization phenomena in nanostructures and condensed-phase systems.</abstract>
    <parentTitle language="eng">New Journal of Physics</parentTitle>
    <identifier type="urn">urn:nbn:de:kobv:526-opus4-17701</identifier>
    <enrichment key="opus.import.data">@articleMedina_2023, doi = 10.1088/1367-2630/acd5f6, url = https://dx.doi.org/10.1088/1367-2630/acd5f6, year = 2023, month = may, publisher = IOP Publishing, volume = 25, number = 5, pages = 053030, author = C Medina and A Ø Lægdsmand and L Ben Ltaief and Z Hoque and A H Roos and L Jurkovičová and O Hort and O Finke and M Albrecht and J Nejdl and F Stienkemeier and J Andreasson and E Klimešová and M Krikunova and A Heidenreich and M Mudrich, title = Long-lasting XUV activation of helium nanodroplets for avalanche ionization, journal = New Journal of Physics, abstract = We study the dynamics of avalanche ionization of pure helium nanodroplets activated by a weak extreme-ultraviolet (XUV) pulse and driven by an intense near-infrared (NIR) pulse. In addition to a transient enhancement of ignition of a nanoplasma at short delay times  fs, long-term activation of the nanodroplets lasting up to a few nanoseconds is observed. Molecular dynamics simulations suggest that the short-term activation is caused by the injection of seed electrons into the droplets by XUV photoemission. Long-term activation appears due to electrons remaining loosely bound to photoions which form stable ‘snowball’ structures in the droplets. Thus, we show that XUV irradiation can induce long-lasting changes of the strong-field optical properties of nanoparticles, potentially opening new routes to controlling avalanche-ionization phenomena in nanostructures and condensed-phase systems.</enrichment>
    <enrichment key="opus.import.dataHash">md5:2286a4ca37664d1b83b0a3628525b361</enrichment>
    <enrichment key="opus.import.date">2023-07-19T07:04:56+00:00</enrichment>
    <enrichment key="opus.import.file">/tmp/phpIjh2Ct</enrichment>
    <enrichment key="opus.import.format">bibtex</enrichment>
    <enrichment key="opus.import.id">64b78b1817cac9.61746059</enrichment>
    <enrichment key="DOI_VoR">https://doi.org/10.1088/1367-2630/acd5f6</enrichment>
    <enrichment key="SourceTitle">C Medina et al 2023 New J. Phys. 25 053030</enrichment>
    <licence>Creative Commons - CC BY - Namensnennung 4.0 International</licence>
    <author>Cristian Medina</author>
    <author>Asbjørn Ørnemark Lægdsmand</author>
    <author>Ltaief Ben Ltaief</author>
    <author>Ziaul Hoque</author>
    <author>Andreas Hult Roos</author>
    <author>Lucie Jurkovičová</author>
    <author>Ondřej Hort</author>
    <author>Ondřej Finke</author>
    <author>Martin Albrecht</author>
    <author>Jaroslav Nejdl</author>
    <author>Frank Stienkemeier</author>
    <author>Jakob Andreasson</author>
    <author>Eva Klimešová</author>
    <author>Maria Krikunova</author>
    <author>Andreas Heidenreich</author>
    <author>Marcel Mudrich</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>nanoplasma</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>helium nanodroplet</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>pump–probe spectroscopy</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>avalanche ionization</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>high-harmonic generation</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>extreme ultraviolet</value>
    </subject>
    <collection role="ddc" number="621">Angewandte Physik</collection>
    <collection role="institutes" number="">Fachbereich Ingenieur- und Naturwissenschaften</collection>
    <collection role="open_access" number="">open_access</collection>
    <collection role="green_open_access" number="1">Gold Open Access</collection>
    <thesisPublisher>Technische Hochschule Wildau</thesisPublisher>
    <file>https://opus4.kobv.de/opus4-th-wildau/files/1770/Medina_2023_New_J._Phys._25_053030.pdf</file>
  </doc>
  <doc>
    <id>2105</id>
    <completedYear>2026</completedYear>
    <publishedYear/>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue>1</issue>
    <volume>16</volume>
    <type>article</type>
    <publisherName>Springer Nature</publisherName>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>1</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">XUV fluorescence as a probe of interatomic coulombic decay of resonantly excited He nanodroplets</title>
    <abstract language="eng">Superfluid He nanodroplets resonantly excited by extreme ultraviolet (XUV) pulses can relax via interatomic coulombic decay (ICD), generally considered an ultrafast process. Here, we introduce a novel approach to probe the dynamics of ICD in He nanodroplets over timescales ranging from femtoseconds to nanoseconds. Our method relies on detecting XUV fluorescence emitted from the nanodroplets as they are driven into a nanoplasma by subsequent intense infrared pulses. Nanoplasma ignition is facilitated by tunnel ionization of XUV-excited He∗ atoms attached to the droplets; it thus serves as a sensitive probe of their relaxation dynamics. The observed nanosecond-scale decay is attributed to ICD between pairs of He∗ atoms undergoing roaming motion on the droplet surface, as supported by quantum-mechanical and classical model calculations.</abstract>
    <parentTitle language="eng">Scientific Reports</parentTitle>
    <identifier type="urn">urn:nbn:de:kobv:526-opus4-21050</identifier>
    <enrichment key="opus.import.date">2026-01-13T09:41:09+00:00</enrichment>
    <enrichment key="opus.source">sword</enrichment>
    <enrichment key="opus.import.user">sword</enrichment>
    <enrichment key="DOI_VoR">https://doi.org/10.1038/s41598-025-34677-x</enrichment>
    <enrichment key="SourceTitle">Sishodia, K., Ltaief, L.B., Scheel, N. et al. XUV fluorescence as a probe of interatomic coulombic decay of resonantly excited He nanodroplets. Sci Rep 16, 1321 (2026). https://doi.org/10.1038/s41598-025-34677-x</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">true</enrichment>
    <licence>Creative Commons - CC BY - Namensnennung 4.0 International</licence>
    <author>Keshav Sishodia</author>
    <author>Ltaief Ben Ltaief</author>
    <author>Niklas Scheel</author>
    <author>István B. Földes</author>
    <author>Andreas Hult Roos</author>
    <author>Martin Albrecht</author>
    <author>Matyáš Staněk</author>
    <author>Lucie Jurkovičová</author>
    <author>Ondrej Hort</author>
    <author>Jaroslav Nejdl</author>
    <author>Ernesto García-Alfonso</author>
    <author>Nadine Halberstadt</author>
    <author>Jakob Andreasson</author>
    <author>Eva Klimešová</author>
    <author>Maria Krikunova</author>
    <author>Sivarama Krishnan</author>
    <author>Andreas Heidenreich</author>
    <author>Marcel Mudrich</author>
    <collection role="ddc" number="535">Licht, Infrarot- und Ultraviolettphänomene</collection>
    <collection role="ddc" number="539">Moderne Physik</collection>
    <collection role="institutes" number="">Fachbereich Ingenieur- und Naturwissenschaften</collection>
    <collection role="open_access" number="">open_access</collection>
    <collection role="Import" number="import">Import</collection>
    <collection role="green_open_access" number="1">Gold Open Access</collection>
    <thesisPublisher>Technische Hochschule Wildau</thesisPublisher>
    <file>https://opus4.kobv.de/opus4-th-wildau/files/2105/s41598-025-34677-x.pdf</file>
  </doc>
</export-example>
