Figure 5: Enhancement ratio for the multiple (3 and 5) dimer configurations compared with a single dimer. In particular, the disc dimer case (blue line) and the bowtie case (red line) are plotted as a function of the interelement distance 𝑑 , for a radius 𝑟 = 4 0 nm and 𝑔 𝑎 𝑝 = 5 nm. The disc dimer and the bowtie are both oriented along the dipole source (see Figure 4).