Figure 7.

(a) Scattering cross section of the optimum nano-dimer (see the geometrical parameters in table 2) dimer nanoaprticle (dimer element width GW=575nm, and gap 50 nm) made from ${\text{SiO}}_2$ (red solid line with open circles), ${\text{TiO}}_2$ (green solid line with open up triangles), and GaP ( blue solid line with open stars). The corresponding absorption cross section are shown as ${\text{SiO}}_2$ (black solid line with closed circles), ${\text{TiO}}_2$ (dark green solid line with closed up triangles), and GaP ( orange solid line with closed stars). (b) Spatial distribution of the normalized scattered electric field of the dimer for the three materials (GaP, ${\text{TiO}}_2$, and ${\text{SiO}}_2$), for the two orthogonal planes of interest (XZ and YZ) at $\lambda =650$ nm.