Effect of non-locality on nanofocusing of surface plasmon field intensity in a conical tip

The propagation of a surface plasmon-polariton toward the tip of a conically shaped metal wire is investigated. The modification of the surface plasmon dispersion relation due to non-local effects is included by employing the hydrodynamic approximation. As found in previous, local calculations, the electric field intensity associated with the surface plasmon increases sharply as the wire becomes narrower. However, the rate of increase is somewhat slower than in the local case.