title: Enhanced coherent emission of terahertz radiation by energy-phase correlation in a bunched electron beam.
abstract: We report the first observation of enhanced coherent emission of terahertz radiation in a compact free electron laser. A radio-frequency (rf) modulated electron beam is passed through a magnetic undulator emitting coherent radiation at harmonics of the rf with a phase which depends on the electron drift velocity. A proper correlation between the energy and phase distributions of the electrons in the bunch has been exploited to lock in phase the radiated field, resulting in over 1 order of magnitude enhancement of the coherent emission.
authors.affiliation: Ente per le Nuove Tecnologie l'Energia e l'Ambiente (ENEA), UTS Tecnologie Fisiche Avanzate, Sezione Laser ed Acceleratori, P.O. Box 65, 00044 Frascati, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Doria
authors.forename: G P
authors.initials: GP
authors.lastname: Gallerano
authors.forename: E
authors.initials: E
authors.lastname: Giovenale
authors.forename: G
authors.initials: G
authors.lastname: Messina
authors.forename: I
authors.initials: I
authors.lastname: Spassovsky