In this paper, the generation of two-dimensional flattop focusing with second order full Poincaré beams
under low numerical aperture focusing condition is proposed and experimentally demonstrated by using
a liquid crystal spatial light modulator (SLM). Different input beam sizes can be accommodated by
conveniently rotating the half-wave plate and adjusting the working distance. Furthermore, the
quantization of the phase pattern loaded onto the SLM has been theoretically and experimentally
studied, which potentially may lead to the fabrication of a compact versatile flattop beam shaper. High
quality flattop profiles with steep edge roll-off can be obtained with this technique.
We perform numerical calculations for the diffraction efficiency of single-sided microprism designs with optical beams
spread over several microprisms. For small angles (less than 1.5 degrees) the far-field diffraction efficiency exceeds 90%
and the far-field angles can be extended to more than 10 degrees with better than 80% diffraction efficiency. For the
microprism array the diffraction angles are discrete and the angles between the diffraction peaks can be covered by
applying a tilted phase to the input field.