title: Generation of coherent broadband photon pulses with a cascaded longitudinal space-charge amplifier.
abstract: The longitudinal space-charge amplifier has been recently proposed by Schneidmiller and Yurkov as an alternative to the free-electron laser instability for the generation of intense broadband radiation pulses [Phys. Rev. ST Accel. Beams 13, 110701 (2010)]. In this Letter, we report on the experimental demonstration of a cascaded longitudinal space-charge amplifier at optical wavelengths. Although seeded by electron beam shot noise, the strong compression of the electron beam along the three amplification stages leads to emission of coherent undulator radiation pulses exhibiting a single spectral spike and a single transverse mode. The on-axis gain is estimated to exceed 4 orders of magnitude with respect to spontaneous emission.
authors.affiliation: Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA. marinelli@slac.stanford.edu
authors.forename: A
authors.initials: A
authors.lastname: Marinelli
authors.forename: E
authors.initials: E
authors.lastname: Hemsing
authors.forename: M
authors.initials: M
authors.lastname: Dunning
authors.forename: D
authors.initials: D
authors.lastname: Xiang
authors.forename: S
authors.initials: S
authors.lastname: Weathersby
authors.forename: F
authors.initials: F
authors.lastname: O'Shea
authors.forename: I
authors.initials: I
authors.lastname: Gadjev
authors.forename: C
authors.initials: C
authors.lastname: Hast
authors.forename: J B
authors.initials: JB
authors.lastname: Rosenzweig