Figure 10.

Extinction calculated cross section of a roughened target (red curve), together with the near-field enhancement: for a smooth stripe in transverse polarization (black square); for a roughened target in transverse polarization (black circle), in longitudinal polarization (empty circle). In the case of the smooth target, the NF enhancement remarkably follows the far-field extinction cross section. On the other hand, the NF enhancement is maximum in the red part of the visible spectral range for the roughened target, in both polarizations.