Search Results

Now showing 1 - 10 of 19
  • Item
    Dynamical studies on the generation of periodic surface structures by femtosecond laser pulses
    (Les Ulis : EDP Sciences, 2013) Rosenfeld, A.; Höhm, S.; Bonse, J.; Krüger, J.
    The dynamics of the formation of laser-induced periodic surface structures (LIPSS) on fused silica upon irradiation with linearly polarized fs-laser pulses (50 fs pulse duration, 800 nm center wavelength) is studied experimentally using a double pulse experiment with cross polarized pulse sequences and a trans illumination femtosecond time-resolved (0.1 ps - 1 ns) pump-probe diffraction approach. The results in both experiments confirm the importance of the ultrafast energy deposition and the laser-induced free-electron plasma in the conduction band of the solids for the formation of LIPSS.
  • Item
    Ultrafast multi-electron dynamics studied with THz-field streaking
    (Les Ulis : EDP Sciences, 2018) Krikunova, M.; Klimešová, E.; Kulyk, O.; Oelze, T.; Schütte, B.; Gebert, T.; Andreasson, J.; Silaev, A.A.
    This article has no abstract.
  • Item
    Nonlinear optical mechanism of forming periodical nanostructures in large bandgap dielectrics
    (Les Ulis : EDP Sciences, 2013) Grunwald, R.; Das, S.K.; Debroy, A.; McGlynn, E.; Messaoudi, H.
    Nonlinear excitation mechanisms of plasmons and their influence on femtosecond-laser induced sub-wavelength ripple generation on dielectric and semiconducting transparent materials are discussed. The agreement of theoretical and experimental data indicates the relevance of the model.
  • Item
    Ultrafast structural and vibrational dynamics of the hydration shell around DNA
    (Les Ulis : EDP Sciences, 2013) Elsaesser, T.; Szyc, LŁ.; Yang, M.
    Two-dimensional infrared spectroscopy in the frequency range of OH- and NH stretch excitations serves for a direct mapping of hydration dynamics around DNA. A moderate slowing down of structural dynamics and resonant OH stretch energy transfer is observed in the DNA water shell compared to bulk water.
  • Item
    Ultrafast inter-ionic charge transfer of transition-metal complexes mapped by femtosecond x-ray powder diffraction
    (Les Ulis : EDP Sciences, 2013) Zamponi, F.; Freyer, B.; Juvé, V.; Stingl, J.; Woerner, M.; Chergui, M.; Elsaesser, T.
    Transient electron density maps are derived from x-ray diffraction patterns of photoexcited [Fe(bpy)3]2+(PF6 -)2 powder. Upon photoexcitation, the 5T 2 quintet state reveals a charge transfer from the PF 6- ions and from the Fe atoms to neighboring bpy units. The charge transfer from the Fe points to a partial and weak charge-transfer character of this state.
  • Item
    Ultrafast relaxation dynamics of highly-excited states in N2 molecules excited by femtosecond XUV pulses
    (Les Ulis : EDP Sciences, 2013) Lucchini, M.; Seung, Kim, K.; Calegari, F.; Kelkensberg, F.; Siu, W.K.; Sansone, G.; Vrakking, M.J.J.; Hochlaf, M.; Nisoli, M.
    We used velocity-map-imaging to measure electronic and nuclear dynamics in N2 molecules excited by a train of attosecond pulses. A time-to-space mapping of autoionization channel is demonstrated. It is found that the autoionization becomes energetically allowed when the two nuclei are still very close (~ 3 Å) and that it can be coherently manipulated by a strong femtosecond infrared pulse.
  • Item
    Femtosecond x-ray diffraction using the rotating crystal method
    (Les Ulis : EDP Sciences, 2013) Freyer, B.; Stingl, J.; Zamponi, F.; Woerner, M.; Elsaesser, T.
    We demonstrate the rotating-crystal method in femtosecond x-ray diffraction. Structural dynamics of a photoexcited bismuth crystal is mapped in a pump-probe scheme by measuring intensity changes of many Bragg reflections simultaneously.
  • Item
    Ultrafast two-dimensional THz spectroscopy of graphene
    (Les Ulis : EDP Sciences, 2013) Bowlan, P.; Martinez Moreno, E.; Reimann, K.; Woerner, M.; Elsaesser, T.
    With two-dimensional THz spectroscopy the dynamics of low-energy carriers in graphene is determined. Both intra- and interband absorption contribute to the observed ultrafast pump-probe signals.
  • Item
    Correlated rotational alignment spectroscopy of isolated molecules and molecular mixtures
    (Les Ulis : EDP Sciences, 2013) Schröter, C.; Kosma, K.; Schultz, T.
    We present a novel multi-pulse spectroscopic method for the correlated analysis of molecular mass, rotational structure and electronic structure. First experiments investigate carbon disulfide and butadiene.
  • Item
    When does an electron exit a tunneling barrier?
    (Les Ulis : EDP Sciences, 2013) Shafir, D.; Soifer, H.; Bruner, B.D.; Dagan, M.; Mairesse, Y.; Patchkovskii, S.; Ivanov, M.Y.; Smirnova, O.; Dudovich, N.
    We probe the dynamics of tunnel ionization via high harmonic generation. We characterize the ionization dynamics in helium atoms, and apply our approach to resolve subtle differences in ionization from different orbitals of a CO 2 molecule.