The use of advanced Bragg reflectors for frequency stabilization and tuning in planar surface-wave oscillators

To achieve high coherence of radiation in oversized Cherenkov surface-wave oscillators (SWO), the use of an additional resonant Bragg reflector of an advanced type based on the coupling of paraxial and quasi-cutoff waves is proposed. Within the framework of the conducted 3D PIC – simulations, it is shown that the reflectors of this type make it possible to provide a stable narrow-band generation regime in SWO of a planar geometry with excitation of the fundamental mode of the slow-wave structure at an oversize parameter (width) of about 7–10 radiation wavelengths. An additional advantage of the proposed planar generator is the possibility of mechanical frequency tuning when changing the gap size of the resonant reflector. The parameters for the implementation of powerful W-band SWO based on the high-current accelerator complex “ELMI”(BINP RAS) have been evaluated.