Feasibility study of optically coupling RF-power at mm waves

At mm-wavelengths, ordinary waveguides show considerable attenuation. Corrugated overmoded waveguides have strongly reduced attenuation, while maintaining stability by introducing the well known pattern of passbands and stopbands. Fields either transform to surface waves with very high losses, or concentrate at the center of the waveguide and propagate with very low loss. The latter, are employed to transport RF-power. Considering the field pattern, optical free space coupling to an accelerator structure, is thinkable. We have investigated the coupling mechanism itself, e.g. field leakage and power losses to the outside and designed a device for optical coupling from a corrugated waveguide into a planar muffin-tin structure