Open AccessSingle shot speckle and coherence analysis of the hard X-ray free electron laser LCLS
Author(s) -
S. Lee,
W. Rosecker,
Christian Gutt,
Birgit Fischer,
Heiko Conrad,
Felix Lehmkühler,
Ingo Steinke,
Diling Zhu,
Henrik T. Lemke,
Marco Cammarata,
David Fritz,
P. Wochner,
M. Castro-Colín,
S. O. Hruszkewycz,
P. H. Fuoss,
G. B. Stephenson,
G. Grübel,
A. Robert
Publication year - 2013
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.21.024647
Subject(s) - optics , speckle pattern , coherence (philosophical gambling strategy) , physics , laser , pulse duration , scattering , coherence length , monochromator , materials science , wavelength , superconductivity , quantum mechanics
The single shot based coherence properties of hard x-ray pulses from the Linac Coherent Light Source (LCLS) were measured by analyzing coherent diffraction patterns from nano-particles and gold nanopowder. The intensity histogram of the small angle x-ray scattering ring from nano-particles reveals the fully transversely coherent nature of the LCLS beam with a number of transverse mode 〈Ms〉 = 1.1. On the other hand, the speckle contrasts measured at a large wavevector yields information about the longitudinal coherence of the LCLS radiation after a silicon (111) monochromator. The quantitative agreement between our data and the simulation confirms a mean coherence time of 2.2 fs and a x-ray pulse duration of 29 fs. Finally the observed reduction of the speckle contrast generated by x-rays with pulse duration longer than 30 fs indicates ultrafast dynamics taking place at an atomic length scale prior to the permanent sample damage.