Experimental investigation of the operation of a parametric free-electron laser which utilises transition and synchrotron radiations

A parametric free-electron laser with a path-bending magnet instead of an undulator was investigated. The initial wave field was formed from transition radiation emitted by an electron bunch at a resonator mirror and from synchrotron radiation emitted during the motion of electrons in a magnetic field. Relativistic electrons were provided by a microtron and an open cavity was used to establish a feedback loop. Coherent stimulated radiation was generated at wave-lengths of 7.2 and 4.2 mm (power 3 W), and of 1 mm (power 1 W).