Submillimeter moderately relativistic free-electron maser

The backward feedback wave of a millimeter-wavelength moderately relativistic Bragg-cavity free-electron auto-oscillator is considered as a wiggler wave in order to produce submillimeter (submm)-wavelength radiation at a harmonic frequency using a single electron beam. For such double-frequency scheme (FEM-ubitron and FEM-scattron) of electron–wave interaction, simulations predict power levels of hundreds of kilowatts at submm wavelengths.