The optical klystron enhancement to a self-amplified spontaneous emission (SASE) free electron laser (FEL) has been deeply studied in theory and in simulations. In this FEL scheme, a relativistic electron beam passes through two undulators, separated by a dispersive section. The latter converts the electron-beam energy modulation produced in the first undulator in density modulation, thus enhancing the free-electron laser gain. We report the first experiment that has been carried out at the FERMI facility in Trieste, of enhancement to a SASE FEL by using the optical klystron scheme. XUV photons have been produced with an intensity several orders of magnitude larger than in pure SASE mode. The impact of the uncorrelated energy spread of the electron beam on the optical klystron SASE performance has been also investigated.

Date Published: 12 May 2015
PDF: 9 pages
Proc. SPIE 9512, Advances in X-ray Free-Electron Lasers Instrumentation III, 95121J (12 May 2015); doi: 10.1117/12.2182415

Published in SPIE Proceedings Vol. 9512:
Advances in X-ray Free-Electron Lasers Instrumentation III
Sandra G. Biedron, Editor(s)