Figure 3. The two THz sources and their calculated emission characteristics.

(a) Working principle of a diffraction radiator (DR) and a simulated beam profile for the horizontal polarization component. (b) Calculation of the intensity spectrum from a DR assuming the screen dimensions and aperture size employed at the prototype facility. (c) Working principle of an undulator source and simulation of the beam profile. (d) (inset) Calculation of the spectrum of an undulator fundamental for a tune to 0.28 THz. Calculated intensity in the fundamental of undulator tunes between 0.1 and 3 THz (red-shaded). All calculations assume a beam energy of 24 MeV and the corresponding acceptance angles of the DR and the undulator optical beamline.