Near-field optical excitation as a dipole-dipole energy transfer process

The process of fluorescence elicitation in the scanning nearfield optical m icroscope (SNOM) is considered as a dipole-dipole resonance energy transfer process between a molecule under study and a SNOM aperture, which can be t reated as a magnetic-type paint dipole, It is shown that such an approach s atisfactorily describes the conditions of the usual SNOM fluorescence exper iments. Fluorescence excitation dependence on the polarization of the incid ent light and medium refraction index have been obtained. The equation to c alculate the resonance dipole-dipole energy transfer radius (which is a nat ural unit of a SNOM's longitudinal resolution) is derived. Those cases wher e such a radius is of the order of the SNOM aperture, and thus single dipol e, can strongly influence the radiation conditions are discussed briefly.