title: Full spatial characterization of a nanofocused x-ray free-electron laser beam by ptychographic imaging.
abstract: The emergence of hard X-ray free electron lasers (XFELs) enables new insights into many fields of science. These new sources provide short, highly intense, and coherent X-ray pulses. In a variety of scientific applications these pulses need to be strongly focused. In this article, we demonstrate focusing of hard X-ray FEL pulses to 125 nm using refractive x-ray optics. For a quantitative analysis of most experiments, the wave field or at least the intensity distribution illuminating the sample is needed. We report on the full characterization of a nanofocused XFEL beam by ptychographic imaging, giving access to the complex wave field in the nanofocus. From these data, we obtain the full caustic of the beam, identify the aberrations of the optic, and determine the wave field for individual pulses. This information is for example crucial for high-resolution imaging, creating matter in extreme conditions, and nonlinear x-ray optics.
authors.affiliation: Institute of Structural Physics, Technische Universität Dresden, Dresden, Germany. schropp@xraylens.de
authors.forename: Andreas
authors.initials: A
authors.lastname: Schropp
authors.forename: Robert
authors.initials: R
authors.lastname: Hoppe
authors.forename: Vivienne
authors.initials: V
authors.lastname: Meier
authors.forename: Jens
authors.initials: J
authors.lastname: Patommel
authors.forename: Frank
authors.initials: F
authors.lastname: Seiboth
authors.forename: Hae Ja
authors.initials: HJ
authors.lastname: Lee
authors.forename: Bob
authors.initials: B
authors.lastname: Nagler
authors.forename: Eric C
authors.initials: EC
authors.lastname: Galtier
authors.forename: Brice
authors.initials: B
authors.lastname: Arnold
authors.forename: Ulf
authors.initials: U
authors.lastname: Zastrau
authors.forename: Jerome B
authors.initials: JB
authors.lastname: Hastings
authors.forename: Daniel
authors.initials: D
authors.lastname: Nilsson
authors.forename: Fredrik
authors.initials: F
authors.lastname: Uhlén
authors.forename: Ulrich
authors.initials: U
authors.lastname: Vogt
authors.forename: Hans M
authors.initials: HM
authors.lastname: Hertz
authors.forename: Christian G
authors.initials: CG
authors.lastname: Schroer