Author: Curry, E.J.
Paper Title Page
Group and Phase Velocity Matching in THz IFEL interaction  
  • E.J. Curry, S.S. Fabbri, P. Musumeci
    UCLA, Los Angeles, California, USA
  • A. Gover
    University of Tel-Aviv, Faculty of Engineering, Tel-Aviv, Israel
  Funding: Work supported by DOE grant DE-FG02-92ER40693 and NSF grant PHY-1415583.
We review results from the recent guided-THz IFEL experiment at the UCLA PEGASUS facility. Using a parallel plate waveguide, the group velocity of a near-single cycle THz pulse was reduced to match electron beam propagation in an undulator, resulting in a ponderomotive interaction sustained for 30 cm. With a 1-uJ THz pulse obtained by optical rectification in a LN source, the projected beam energy distribution increased from a full peak width of 30 keV to more than 100 keV. When using a long (multi-ps) electron beam, longitudinal phase-space measurements reveal the snake-like energy modulation from the ps-scale THz pulse. Using a short beam configuration, we also measure bunch compression, limited by the available drift length to a factor of two. Finally, we explore the application of this technique to amplification of the THz seed using the 1-D multi-frequency simulation code we have developed for this novel zero-slippage interaction scheme.