Quasi-optical theory of relativistic submillimeter Cherenkov amplifier and oscillators

Within the quasi-optical approach, we study evanescent waves propagation along a periodically corrugated surface and their excitation by a relativistic electron beam. The main features of amplifier and oscillators schemes are described including the increments, starting currents, electron efficiency and forming of self-consistent spatial structure of the radiation field. The feasibility of realization of relativistic surface-wave devices in the submillimeter wavelength range is demonstrated.