title: High-gain lasing and polarization switch with a distributed optical-klystron free-electron laser.
abstract: This Letter reports the first experimental results from the world's first distributed optical-klystron (DOK) free-electron laser (FEL), the DOK-1 FEL, at Duke University. The DOK-1 FEL is a hybrid system, comprised of four wigglers: two horizontal and two helical. With the DOK-1 FEL, we have obtained the highest FEL gain among all storage ring based FELs at 47.8% (+/-2.7%) per pass. We have also demonstrated that the FEL gain can be enhanced by increasing electron bunching using wigglers with a different polarization. Furthermore, we have realized controlled polarization switches of the FEL beam by a nonoptical means through the manipulation of a buncher magnet.
authors.affiliation: Department of Physics, Duke University, Durham, North Carolina 27708-0319, USA. wu@fel.duke.edu
authors.forename: Y K
authors.initials: YK
authors.lastname: Wu
authors.forename: N A
authors.initials: NA
authors.lastname: Vinokurov
authors.forename: S
authors.initials: S
authors.lastname: Mikhailov
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: V
authors.initials: V
authors.lastname: Popov