Non-ring perfect optical vortices with p-th order symmetry generated using composite diffractive optical elements

Abstract

A “perfect” optical vortex (POV), a ring-shaped singular beam whose diameter does not scale with its topological charge, is now being extensively studied owing to its important practical applications ranging from optical trapping and manipulation of microscale objects to laser material processing with structured beams. At the same time, the ability to shape the intensity distribution of the POV in a controlled manner is of crucial importance for the mentioned applications; however, only circular- or elliptical-shaped POVs were demonstrated so far. Here, we propose and design pure phase diffractive optical elements (DOEs) with an optimized composite transmission function allowing high-efficient generation of non-ring-shaped POVs with p-th order symmetry. We demonstrate the generation of POVs with the desired topological charge, transverse size, and variable “polygon-like” lateral intensity distribution. Our experimental results are in good agreement with theoretical and simulation predictions. The proposed DOEs can be characterized by high conversion efficiency (more than 60%), thus substantiating their applicability for high-performing optical manipulation and advanced laser nanopatterning.