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Author: Fennel, Thomas × End date: 2019 × DDC: 530 × Publisher: [London] : IOP × WGL Institute: MBI ×

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    All-optical spatio-temporal control of electron emission from SiO2 nanospheres with femtosecond two-color laser fields
    ([London] : IOP, 2019) Liu, Qingcao; Zherebtsov, Sergey; Seiffert, Lennart; Skruszewicz, Slawomir; Zietlow, Dominik; Ahn, Seongjin; Rupp, Philipp; Wnuk, Pawel; Sun, Shaohua; Kessel, Alexander; Trushin, Sergei; Schlander, Annika; Kim, Dongeon; Rühl, Eckart; Ciappina, Marcelo F.; Tiggesbäumker, Josef; Gallei, Markus; Fennel, Thomas; Kling1, Matthias F.
    Field localization by nanostructures illuminated with laser pulses of well-defined waveform enables spatio-temporal tailoring of the near-fields for sub-cycle control of electron dynamics at the nanoscale. Here, we apply intense linearly-polarized two-color laser pulses for all-optical control of the highest energy electron emission from SiO2 nanoparticles. For the size regime where light propagation effects become important, we demonstrate the possibility to control the preferential emission angle of a considerable fraction of the fastest electrons by varying the relative phase of the two-color field. Trajectory based semi-classical simulations show that for the investigated nanoparticle size range the directional steering can be attributed to the two-color effect on the electron trajectories, while the accompanied modification of the spatial distribution of the ionization rate on the nanoparticle surface has only a minor effect. © 2019 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaft
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    Recombination dynamics of clusters in intense extreme-ultraviolet and near-infrared fields
    ([London] : IOP, 2015) Schütte, Bernd; Oelze, Tim; Krikunova, Maria; Arbeiter, Mathias; Fennel, Thomas; Vrakking, Marc J. J.; Rouzée, Arnaud
    We investigate electron-ion recombination processes in clusters exposed to intense extreme-ultraviolet (XUV) or near-infrared (NIR) pulses. Using the technique of reionization of excited atoms from recombination (REAR), recently introduced in Schütte et al (2014 Phys. Rev. Lett. 112 253401), a large population of excited atoms, which are formed in the nanoplasma during cluster expansion, is identified under both ionization conditions. For intense XUV ionization of clusters, we find that the significance of recombination increases for increasing cluster sizes. In addition, larger fragments are strongly affected by recombination as well, as shown for the case of dimers. We demonstrate that for mixed Ar–Xe clusters exposed to intense NIR pulses, excited atoms and ions are preferentially formed in the Xe core. As a result of electron-ion recombination, higher charge states of Xe are efficiently suppressed, leading to an overall reduced expansion speed of the cluster core in comparison to the shell.