Evanescent and propagating electromagnetic fields in scattering from point-dipole structures

We investigate the propagating and evanescent field contributions in the sc attering of an electromagnetic field from a collection of interacting elect ric point dipoles. Having applications of scanning near-field optical micro scopy (SNOM) in mind, we study three different geometries of dipoles placed close to a bulk surface. One of them is chosen to allow a direct compariso n with the results recently put forward in the literature [J. Mod. Opt. 44, 327 (1997)] and to point out the discrepancies in the near zone between th e held decompositions applied in that paper and in our work. The other two geometries have been selected to illustrate SNOM action in the illumination and collection modes. Within the point-dipole model we investigate the eff ects of the probe-dipole polarization on the propagating and evanescent fie lds in the sample-probe system during the scanning of the probe at differen t heights above the sample. (C) 2001 Optical Society of America.