Evanescent field coupling of dipole to a surface: configurational resonance at long distances

Light excited dipole interacts with nearby surfaces and, at certain dipole-surface distances, configurational resonances happen. The evanescent field coupling can be separately calculated and the configurational resonances due to the evanescent coupling may happen at long dipole-surface distances. The numerical results of field enhancement for silver particle-surface system are provided and discussed. In the light of the theory, we also predict that selective (from the homogeneous field) detection of the evanescent field may be realizable, especially at these resonance distances.