Fig. 1: Geometry. 64nm wide gold wire with a 6nm deep groove. (Mirror symmetry at the center plane applied.)

Plasmonic antennas have been proposed for applications like, e.g., ultra-sensitive bio-sensing. When a plasmonic resonator includes a small geometrical feature like a tiny V-groove, the local field intensities of the electromagnetic field can be enhanced by several orders of magnitude. However, the accurate simulation of such field enhancements can be numericallly challenging.
We use adaptive finite elements for the efficient simulation of a V-groove antenna.

Fig. 2: Detail of the finite element mesh.

Figure 1 shows a typical geometry of a V-groove antenna. The geometry is invariant in the third spatial dimension. A monochromatic light field is incident from the top. Figure 2 shows the FEM mesh created by JCMgeo. Figure 3 shows the wavelength-dependent local field enhancement. A typical electromagnetic field intensity distribution is shown in Figure 4.