The localized and enhanced optical near-field on the asymmetric metal-coated dielectric probe

In this paper, we investigated the basic characteristics of the maximum optical intensity at the tip created by nanofocusing in the SPP metal-coated conical dielectric probe with asymmetric shape by the volume integral equation method. We consider the cases of radially polarized and linearly polarized incident Gaussian beams and found that the asymmetric SPP conical probe is valid for incident linearly polarized beam. Since the degree of the asymmetric shape of the probe affects significantly the maximum enhanced optical intensity at the tip for incident RP and LP beams, the findings of this study demonstrate that asymmetric conical probes must be carefully designed and fabricated.