1. Ultra-compact THz FEL and FEL amplifier
2. Highly bunched beam from Photoinjector for FEL applications
The scope of my presentation covers my experiences on THz FEL oscillator, superradiant FEL, and FEL amplifier. I will start my talk on the ultra-compact far-infrared FEL oscillator that I built at Stanford University when I was a graduate student there. This FEL oscillator employs a MeV thermionic gun as its injector, emitting far-IR radiation at 85 microns from a hole-coupled cavity. In the 2nd part of my talk, I will then present our recent study on THz superradiant FEL to achieve MW peak radiation power without a laser oscillator. Among several schemes to generate THz bunched electron beams for the superradiant FEL, laser-gated and mask-grated photoemission from a photocathode are my emphases. For applications demanding spectral and mode purity, a laser amplifier is often superior to an oscillator. Recently kW and sub-kW THz seed sources are becoming available from optical technologies. I will report our recent effort in designing a high peak- and average-power THz FEL amplifier with tunablity between 0.5~7 THz. If time allows, I might also talk about our on-going effort on the realization of table-top far-infrared FEL driven by a laser modulated keV electron beam.
