Femtosecond point-projection microscopy and low-energy electron diffraction


There is strong interest in ultrafast experimental techniques that provide direct structural information, e.g. the structural evolution of a crystal or a molecule on the time scale of the fundamental vibrational modes. There has been tremendous progress in the development of femtosecond electron and x-ray diffraction and imaging techniques optimally suited for three-dimensional systems. The highest scattering cross-section, hence the highest sensitivity to structural dynamics in low-dimensional materials, however, is obtained with sub-keV electrons. We developed a femtosecond low-energy electron diffraction and imaging apparatus based on a laser-triggered field emission electron source. The current operation modes include diffraction in transmission and point projection microscopy.

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Related publications:

  • M. Müller, V. Kravtsov, A. Paarmann, M.B. Raschke, and R. Ernstorfer:
    Nanofocused plasmon-driven sub-10 fs electron point source.
    ACS Photonics 3, 611 (2016), [doi: 10.1021/acsphotonics.5b00710].
  • M. Müller, A. Paarmann, and R. Ernstorfer:
    Femtosecond electrons probing currents and atomic structure in nanomaterials.
    Nature Communications 5, 5292 (2014), [doi: 10.1038/ncomms6292].
    open access: arXiv:1405.4992
  • S. Lüneburg, M. Müller, A. Paarmann, and R. Ernstorfer:
    Microelectrode for energy and current control of nanotip field electron emitters.
    Appl. Phys. Lett. 103, 213506 (2013), [doi: 10.1063/1.4831735].
  • M. Müller, A. Paarmann, C. Xu, and R. Ernstorfer:
    Coherent Electron Source for Ultrafast Electron Diffraction and Imaging.
    EPJ Web of Conferences 41, 10007 (2013).
  • A. Paarmann, M. Gulde, M. Müller, S. Schäfer, S. Schweda, M. Maiti, C. Xu, T. Hohage, F. Schenk, C. Ropers, and R. Ernstorfer:
    Coherent femtosecond low-energy single-electron pulses for time-resolved diffraction and imaging: A numerical study.
    J. Appl. Phys. 112, 113109 (2012), [doi: 10.1063/1.4768204].