title: Observation of anomalously large spectral bandwidth in a high-gain self-amplified spontaneous emission free-electron laser.
abstract: Observation of ultrawide bandwidth, up to 15% full-width, high-gain operation of a self-amplified spontaneous emission free-election laser (SASE FEL) is reported. This type of lasing is obtained with a strongly chirped beam (deltaE/E approximately 1.7%) emitted from the accelerator. Because of nonlinear pulse compression during transport, a short, high current bunch with strong mismatch errors is injected into the undulator, giving high FEL gain. Start-to-end simulations reproduce key features of the measurements and provide insight into mechanisms, such as angular spread in emitted photon and electron trajectory distributions, which yield novel features in the radiation spectrum.
authors.affiliation: Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA.
authors.forename: G
authors.initials: G
authors.lastname: Andonian
authors.forename: A
authors.initials: A
authors.lastname: Murokh
authors.forename: J B
authors.initials: JB
authors.lastname: Rosenzweig
authors.forename: R
authors.initials: R
authors.lastname: Agustsson
authors.forename: M
authors.initials: M
authors.lastname: Babzien
authors.forename: I
authors.initials: I
authors.lastname: Ben-Zvi
authors.forename: P
authors.initials: P
authors.lastname: Frigola
authors.forename: J Y
authors.initials: JY
authors.lastname: Huang
authors.forename: L
authors.initials: L
authors.lastname: Palumbo
authors.forename: C
authors.initials: C
authors.lastname: Pellegrini
authors.forename: S
authors.initials: S
authors.lastname: Reiche
authors.forename: G
authors.initials: G
authors.lastname: Travish
authors.forename: C
authors.initials: C
authors.lastname: Vicario
authors.forename: V
authors.initials: V
authors.lastname: Yakimenko