Enhanced coherent emission of terahertz radiation by energy-phase correlation in a bunched electron beam.
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.
Doria
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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.
Gallerano
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Giovenale
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Messina
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Spassovsky
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