Achievement of regular-polygon-like focus through tightly focusing phase modulated radially polarized beam

Abstract

In this paper, we propose a facile and universal method to design a phase diffractive optical element (DOE) in tightly focusing system for achieving regular-polygon-like focus, including flattop focus and ring-like focus on the focal plane. The edges of the regular-polygon-like focus can be simply adjusted by adjusting the amount of subareas on the DOE. For a specified regular polygon distribution, the focus can be modulated to flattop focus as well as ring-like focus through adjusting only one parameter. As a demonstration, flattop focus as well as ring-like focus with focal distributions as regular triangle, square, pentagon, hexagon and heptagon are well achieved on the focal plane. It provides a simple method to achieve regular-polygon-like focus, which may find potential applications in optical manipulation and material processing fabrications.