Decomposition of the point-dipole field into homogeneous and evanescent parts

In near-field optics the resolution and sensitivity of measurements depend on the abundance of evanescent waves in relation to propagating waves. The electromagnetic field propagator is related to the scalar spherical wave, f or which the Weyl expansion is a half-space representation containing both evanescent and homogeneous plane waves. Making use of these results, we dec ompose the dyadic free-space Green function into its evanescent and homogen eous parts and show that some approaches put forward in the Literature are inconsistent with this formulation. We express the results in a form that i s suitable for numerical computation and illustrate the held decomposition for a point dipole in some typical cases. [S1063-651X(99)05001-1].