Design of axially super-resolving phase pupil filter for high-numerical aperture applications

The method of generalized projection was used to design a phase pupil filter that super-resolves the axial point-spread-function (PSF) by 29% while holding the side-lobe intensities at below 52% of the peak intensity in the non-paraxial regime. The resulting phase filter has a binary 0/π eleven-zone rotationally symmetric profile. Although the filter's performance is theoretically satisfactory, it can be greatly compromised by imperfections introduced during experimental implementation. Such imperfections include fabrication errors, surface quality variation, and optical misalignment. A model based on vectorial diffraction was used to simulate and analyze quantitatively the effect of these imperfections on the superresolved PSF.