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Author: Seiffert, Lennart × DDC: 530 ×

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    Quenching of material dependence in few-cycle driven electron acceleration from nanoparticles under many-particle charge interaction
    (London [u.a.] : Taylor & Francis, 2016-12-25) Rupp, Philipp; Seiffert, Lennart; Liu, Qingcao; Süßmann, Frederik; Ahn, Byungnam; Förg, Benjamin; Schäfer, Christian G.; Gallei, Markus; Mondes, Valerie; Kessel, Alexander; Trushin, Sergei; Graf, Christina; Rühl, Eckart; Lee, Jinwoo; Kim, Min Su; Kim, Dong Eon; Fennel, Thomas; Kling, Matthias F.; Zherebtsov, Sergey
    The excitation of nanoscale near-fields with ultrashort and intense laser pulses of well-defined waveform enables strongly spatially and temporally localized electron emission, opening up the possibility for the generation of attosecond electron pulses. Here, we investigate the electron photoemission from isolated nanoparticles of different materials in few-cycle laser fields at intensities where the Coulomb field of the ionized electrons and residual ions significantly contribute to the electron acceleration process. The dependences of the electron cut-off energy on the material’s dielectric properties and electron binding energy are investigated systematically in both experiments and semi-classical simulations. We find that for sufficiently high near-field intensities the material dependence of the acceleration in the enhanced near-fields is quenched by many-particle charge-interaction.
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    Onset of charge interaction in strong-field photoemission from nanometric needle tips
    (Berlin : de Gruyter, 2021) Schötz, Johannes; Seiffert, Lennart; Maliakkal, Ancyline; Blöchl, Johannes; Zimin, Dmitry; Rosenberger, Philipp; Bergues, Boris; Hommelhoff, Peter; Krausz, Ferenc; Fennel, Thomas; Kling, Matthias F.
    Strong-field photoemission from nanostructures and the associated temporally modulated currents play a key role in the development of ultrafast vacuum optoelectronics. Optical light fields could push their operation bandwidth into the petahertz domain. A critical aspect of their functionality in the context of applications is the impact of charge interaction effects. Here, we investigated the photoemission and photocurrents from nanometric tungsten needle tips exposed to carrier-envelope phase (CEP)-controlled few-cycle laser fields. We report a characteristic rapid increase in the intensity-rescaled cutoff energies of emitted electrons beyond a certain intensity value. By comparison with simulations, we identify this feature as the onset of charge-interaction dominated photoemission dynamics. Our results are anticipated to be relevant also for the strong-field photoemission from other nanostructures, including photoemission from plasmonic nanobowtie antennas used in CEP-detection and for PHz-scale devices.
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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