Author: Ilchen, M.
Paper Title Page
THA02 Experimental Characterization of FEL Polarization Control with Cross Polarized Undulators 644
  • E. Ferrari, E. Allaria, G. De Ninno, B. Diviacco, D. Gauthier, L. Giannessi, G. Penco, C. Spezzani
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • J. Buck, M. Ilchen
    XFEL. EU, Hamburg, Germany
  • G. De Ninno, D. Gauthier
    University of Nova Gorica, Nova Gorica, Slovenia
  • L. Giannessi
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • Z. Huang, A.A. Lutman
    SLAC, Menlo Park, California, USA
  • G. Lambert, B. Mahieu
    LOA, Palaiseau, France
  • J. Viefhaus
    DESY, Hamburg, Germany
  Polarization control of the coherent radiation is becoming an important feature of recent and future short wavelength free electron laser facilities. While polarization tuning can be achieved taking advantage of specially designed undulators, a scheme based on two consecutive undulators emitting orthogonally polarized fields has also been proposed. Developed initially in synchrotron radiation sources, crossed polarized undulator schemes could benefit from the coherent emission that characterize FELs. In this work we report the first detailed experimental characterization of the polarization properties of an FEL operated with crossed polarized undulators in the Soft-X-Rays. Aspects concerning the average degree of polarization and the shot to shot stability are investigated together with a comparison of the performance of various schemes to control and switch the polarization  
slides icon Slides THA02 [5.383 MB]  
Prospects of Stimulated X-ray Raman Scattering with Free-Electron Laser Sources  
  • N. Rohringer, V. Kimberg, C. Weninger
    Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
  • M. Agaker, R. Feifel, M. Mucke, J. Nordgren, J.E. Rubensson, C. Sathe, R. Squibb, V. Zhaunerchyk
    Uppsala University, Uppsala, Sweden
  • C. Bostedt, J.D. Bozek, S. Carron Montero, R.N. Coffee, J. Krzywinski, A. Lindahl, A. Lutmann, T.J. Maxwell
    SLAC, Menlo Park, California, USA
  • B. Erk, D. Rolles
    DESY, Hamburg, Germany
  • M. Ilchen
    XFEL. EU, Hamburg, Germany
  • T. Kierspel, J. Küpper, T.G. Mullins
    University of Hamburg, Hamburg, Germany
  • O.D. Mücke
    CFEL, Hamburg, Germany
  • M. Purvis, J.J. Rocca, D.P. Ryan
    CSU, Fort Collins, Colorado, USA
  • A. Sanchez-Gonzalez
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  XFELs might open the pathway to transfer non-linear spectroscopic techniques to the x-ray domain, to study electron motion at unprecedented time and length scales. A promising x-ray pump probe technique is based on stimulated electronic x-ray Raman scattering. I will present the first experimental demonstration of stimulated electronic x-ray Raman scattering in a gas sample of neon*. Despite the limited spectral coherence of SASE XFELs, high-resolution spectra can be obtained by statistical methods, opening the path to coherent stimulated x-ray Raman spectroscopy. An extension of these ideas to molecules** and the results of a recent experiment in CO will be discussed. The high-gain regime, involving exponential amplification and strong-field effects will be contrasted to stimulated scattering at moderate x-ray intensities, more appropriate for spectroscopic studies. A critically assessment of the feasibility of nonlinear x-ray spectroscopic techniques and requirements on the stability and pulse parameters of XFEL sources that could enable these new techniques, will be presented.
* C. Weninger et al., Phys. Rev. Lett. 111, 233902 (2013)
** C. Weninger and N. Rohringer, Phys Rev A 88, 053421 (2013)
slides icon Slides FRA01 [3.771 MB]