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. (c) 2008 Optical Society of America.