title: Tunable few-cycle and multicycle coherent terahertz radiation from relativistic electrons.
abstract: We report the generation of tunable, narrow-band, few-cycle and multicycle coherent terahertz (THz) pulses from a temporally modulated relativistic electron beam. We demonstrate that the frequency of the THz radiation and the number of the oscillation cycles of the THz electric field can be tuned by changing the modulation period of the electron beam through a temporally shaped photocathode drive laser. The central frequency of the THz spectrum is tunable from ∼0.26 to 2.6 THz with a bandwidth of ∼0.16  THz.
authors.affiliation: National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Yuzhen
authors.initials: Y
authors.lastname: Shen
authors.forename: Xi
authors.initials: X
authors.lastname: Yang
authors.forename: G L
authors.initials: GL
authors.lastname: Carr
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Hidaka
authors.forename: James B
authors.initials: JB
authors.lastname: Murphy
authors.forename: Xijie
authors.initials: X
authors.lastname: Wang