Nanoring as a magnetic or electric field sensitive nano-antenna for near-field optics applications

In this paper we investigate, in the visible range, the behavior of the electromagnetic near-field, perturbed by a metal nanoring. The vectorial study which is based on FDTD simulation, consists of comparing in the near zone, the electric and magnetic field distributions while interacting with the metal nanoring, according to the incident polarization state. Both image distributions and chromatic spectra are computed and analyzed. The purpose of this work is the enhancement of either the electric or the magnetic emission/detection capability of nanoring according to illumination conditions. Such nano-objects can be seen as particular selective nanodevices playing the role of nano-antennas usable in near-field microscopy as an alternative solution to usual tips.