Near field enhancement by magnetized surface plasmon polaritons at THz band

The near field radiation at the tip of a magnetized InSb cylinder is enhanced by tuning the external magnetic field. Cylindrical geometries that supports magnetized surface plasmon polaritons (SPPs) are proposed. In order to further enhance the near field strength at the tip of the cylinder, an improved geometry, i.e. the conical-cylinder structure, where a conical is attached at the top of the base cylinder is proposed. Three-dimensional finite-difference time-domain (FDTD) simulations demonstrate that the near field distribution at the tip of the cylinder can be enhanced at 6THz by tuning the external magnetic field. In addition, the conical-cylinder geometry can render an even stronger EM field distribution at the tip. The proposed geometries of magnetized plasmonic cylinders are meaningful for applications like micrometer scale antennas, electronic microscopes, biosensors etc.