Filters

2016 - 20172

More filters

2022 - 20232
Reset filters

Settings

Author: Ivanov, Misha Yu × Author: Patchkovskii, Serguei × Start date: 2010 × WGL Institute: MBI ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Strong-field assisted extreme-ultraviolet lasing in atoms and molecules
    ([Bad Honnef] : Dt. Physikalische Ges., 2017-07-10) Bredtmann, Timm; Patchkovskii, Serguei; Ivanov, Misha Yu
    Using ab-initio simulations, we demonstrate amplification of extreme-ultraviolet (XUV) radiation during transient absorption in a high-harmonic generation type process using the example of the hydrogen atom. The strong IR driving field rapidly depletes the initial ground state while populating excited electronic states through frustrated tunnelling, thereby creating a population inversion. Concomitant XUV lasing is demonstrated by explicit inclusion of the XUV seed in our simulations, allowing a thorough analysis in terms of this transient absorption setup. Possibilities for increasing this gain, e.g. through preexcitation of excited states, change of the atomic gain medium or through multi-center effects in molecules, are demonstrated. Our findings should lead to a reinterpretation of recent experiments.
  • Thumbnail Image
    Item
    Strong-field ionization of clusters using two-cycle pulses at 1.8 μm
    ([London] : Macmillan Publishers Limited, part of Springer Nature, 2016) Schütte, Bernd; Ye, Peng; Patchkovskii, Serguei; Austin, Dane R.; Brahms, Christian; Strüber, Christian; Witting, Tobias; Ivanov, Misha Yu; Tisch, John W. G.; Marangos, Jon P.
    The interaction of intense laser pulses with nanoscale particles leads to the production of high-energy electrons, ions, neutral atoms, neutrons and photons. Up to now, investigations have focused on near-infrared to X-ray laser pulses consisting of many optical cycles. Here we study strong-field ionization of rare-gas clusters (103 to 105 atoms) using two-cycle 1.8 μm laser pulses to access a new interaction regime in the limit where the electron dynamics are dominated by the laser field and the cluster atoms do not have time to move significantly. The emission of fast electrons with kinetic energies exceeding 3 keV is observed using laser pulses with a wavelength of 1.8 μm and an intensity of 1 × 1015 W/cm2, whereas only electrons below 500 eV are observed at 800 nm using a similar intensity and pulse duration. Fast electrons are preferentially emitted along the laser polarization direction, showing that they are driven out from the cluster by the laser field. In addition to direct electron emission, an electron rescattering plateau is observed. Scaling to even longer wavelengths is expected to result in a highly directional current of energetic electrons on a few-femtosecond timescale.