Experimental demonstration of an electromagnetically pumped free-electron laser with a cyclotron-harmonic idler

Abstract

A three-wave, free-electron laser was operated with a powerful 8.4-GHz electromagnetic "pump" wave replacing the usual magnetostatic wiggler. The presence of a uniform axial magnetic field Bo produced cyclotron-harmonic "idler" waves. Peaks in the emission spectrum corresponding to cyclotron harmonics were observed covering a frequency range from 16.5 to 130 GHz. The frequency spectrum of this novel free-electron laser mechanism was tuned continuously by variation of Bo.