Reconstruction of the dielectric contrast profile from near-field data

A perturbative model describing the influence of topography and dielectric contrast on the near field scattered by an inhomogeneous surface is derived. It is shown that the near-field intensity is sensitive to the integral of the dielectric constrast in the vertical direction across the sample. A solution to the inverse problem from a measurement of the near-field intensity along a line at a constant height above the surface is reported.