Interferometric measurement data obtained from a rectangular grating (SiMETRICS RS-N, Λ = 300 nm) using royalblue (a) TM and (b) TE polarized light through a microsphere (SiO₂, 5–9 μm diam.), simulated data sets of a similar grating with (c) TM and (d) TE polarized light assuming a microcylinder of 5 μm diameter. The corresponding 3D spatial frequency representations are depicted in (e) – (h). The results shown in (a) and (e) are also analyzed in [11].