Far-IR/THz Radiation from the Jefferson Lab FEL Energy Recovered Linac

摘要

The Free Electron Laser at Jefferson Lab is based on a photo-injected energyrecovered linac, and currently uses a 40 MeV electron beam with an average current of 5 mA. The electron bunches are extremely short with FWHM values that are in the few hundred femtosecond regime. These electron bunches pass a chicane around the optical cavity, and therefore emit synchrotron radiation. In the far-IR region, the wavelength of light being emitted quickly approaches that of the electron bunch length, giving rise to multiparticle coherent enhancement. The result is a broadband spectrum more than 5 orders of magnitude brighter than can be obtained from incoherent synchrotron IR sources. We will discuss preliminary measurements of this radiation, and applications to spectroscopy and imaging.