Interaction of nanoparticles with substrates: effects on the dipolar behaviour of the particles.

In this work, we present a numerical analysis of the surface electric field of a metallic nanoparticle (either 2D or 3D) interacting with a flat substrate underneath. The influence of the distance to the substrate, particle size, the surrounding media and the substrate optical properties is analyzed as a function of the incident wavelength. We show that these are crucial factors that change the field distribution associated to the dipolar behavior of the particle. A useful parameter for illustrating the changes in the angular distribution is theta(max), the angle at which the maximum of the surface electric field is located.