Resumen:
In this paper, we investigate theoretically the electromagnetic fieild enhancement arising from excitation of silver and gold nanowires (NWs) of finete wavelength, capable of sustaining surface plasmon resonances of different multipole order, using the Discrete Dipole Approximation (DDA). The influence of NW length on the degreeof enhancement and confinement of the electromagnetic field for each surface plasmon mode is analyzed bya 3D mapping of the near field for different planes around the NW as well by calculating its variation withdistance along two different directions, one parallel to and the other perpendicular to the NW axis,outsideof the NW. It was found that the enhancement is still significant at relative large distances from the NW end,its decay being of much longer range than that predicted by a simple dipole approximation, especially at near-infrared wavelengths