Figure 3: (a) Field enhancement for the disc dimer (blue line) and the bowtie (red line) on top of the Fabry-Perot structure as a function of the 𝑔 𝑎 𝑝 distance for a radius 𝑟 = 4 0 nm. The effect of realistic lossy materials is also shown (red dotted line) for the bowtie configuration. (b) Field enhancement as a function of the radius 𝑟 when 𝑔 𝑎 𝑝 = 5 nm. For both panels, the dimer and the bowtie are both oriented along the dipole source (see Figure 1).