title: Multicolor operation and spectral control in a gain-modulated x-ray free-electron laser.
abstract: We show that the spectral properties of a self-amplified spontaneous emission x-ray free-electron laser can be controlled by modulating the gain in magnetic undulators, thus producing one or several spectral lines within a single few femtosecond pulse. By varying the magnetic field along the undulator and the electron beam transport line, the system we demonstrate can tailor the x-ray spectrum to optimally meet numerous experimental requirements for multicolor operation.
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: A
authors.initials: A
authors.lastname: Marinelli
authors.forename: A A
authors.initials: AA
authors.lastname: Lutman
authors.forename: J
authors.initials: J
authors.lastname: Wu
authors.forename: Y
authors.initials: Y
authors.lastname: Ding
authors.forename: J
authors.initials: J
authors.lastname: Krzywinski
authors.forename: H-D
authors.initials: HD
authors.lastname: Nuhn
authors.forename: Y
authors.initials: Y
authors.lastname: Feng
authors.forename: R N
authors.initials: RN
authors.lastname: Coffee
authors.forename: C
authors.initials: C
authors.lastname: Pellegrini