Axial Field Engineering In The Nonparaxial Domain

The design of axially super-resolving phase pupil filters based on the scalar theory of diffraction is limited to low numerical aperture (NA) focusing. To account for the non-paraxiality encountered in high-NA optical systems, we propose a design procedure based on the method of generalized projections that incorporates the electromagnetic theory of diffraction. A solution is identified that narrows the axial intensity of the central lobe by 29% while maintaining the side lobe intensity below 52% of the peak intensity. It is found that solutions obtained with this method depend strongly on the applied constraints and the starting pupil filter