Figure 1
From: Double-way spectral tunability for the control of optical nanocavity resonance
(a) Schematic of the BNA engraved at the tip apex of radius R. (b) Enhancement factor of the BNA-on-tip measured 15 nm in front of its apex and defined as the ratio of the intensity with BNA by the same intensity calculated without metal coating. The inset of (b) shows the intensity distribution (logarithmic scale) in the yOz longitudinal plane to point out the light confinement occurring in the gap zone.
