Concept of a miniaturised free-electron laser with field emission source

The design considerations and the experimental steps for the realisation of a miniaturised free-electron laser, which uses the Smith–Purcell effect to generate THz-radiation, are presented. As an electron source a miniaturised field emitter cathode with integrated extractor and focusing optics is employed. Due to the very high brightness of this source an intensive portable and tuneable source for the near- and far-infrared is expected. on-beam-induced deposition and computer control is used to build the field electron emitter with an extractor and focusing lens on a prefabricated wiring pattern incorporating a metal line grating. This is a novel fabrication technique and allows us to build an extremely powerful miniaturised source. eld electron source with one single emitter delivers an emission current as high as 1 mA at 70 V extraction voltage and carries a current density of 20 MA/cm2 in the wire without being destroyed.