Cherenkov maser experiments based on a 2D periodic surface lattice

Numerical finite difference time domain and Particle-In-Cell simulations have demonstrated an electron wave interaction in a Cherenkov maser utilizing a cylindrical two-dimensional (2D) Periodic Surface Lattice (PSL) as a mode selective cavity [1-8]. Optimization of this structure's physical properties resulted in the design of a cavity with 16 longitudinal periods of 1.6 mm length, 7 azimuthal variations and an unperturbed inner radius of 4 mm. In numerical simulations this design produces an output power of 300 kW with 10 % efficiency at a frequency of 103.6 GHz. A proof of principle experiment demonstrating electron beam interaction with a wave formed when the volume field and surface field are coupled in an oversized 2D PSL cavity will be presented. The application of PSLs has the potential to deliver high average power, efficient, compact electromagnetic wave sources in the challenging THz frequency range