Coupling High-K Fields In Surface Plasmonic Radiation Generators to Free Space Radiation Using Curved Hyperbolic Metamaterial

Electron-beam driven THz Cherenkov radiations can be generated using the concept of surface plasmonic 1 . These sources mainly exploit the surface plasmonic induced on the interface layer by an electron beam, which are then coupled into the underlying substrate. Initial experiment work has also been reported 2 .The coupling of these highly confined surface modes into the substrate however demands, momentum matching and has been explored by using placing a buffer layer , grating etc . 1 , 3 . Recently, we have shown that a Graphene-dielectric multilayer Hyperbolic Metamaterial (G-HMM) can be used as a substrate where the bulk modes of the G-HMM ensures the coupling takes place , for THz Generation [4] . In all such sources, however, what remains unexplored is the mechanism that couples the generated high-k radiations from the substrate into the free space.