A Hybrid Iterative Algorithm for Generating Polygonal Flat-Top Beams with High Energy Utilization Rate

Flat-top beams with uniform intensity distribution and well-defined profiles have broad application prospects. However, current design methods can only achieve circular or square beam shaping. Recently, a method enabling the generation of polygonal flat-top beams has been proposed, yet its energy utilization rate is limited at the 70% level only. To solve this issue, we propose a hybrid iterative algorithm for the purpose of generating polygonal flat-top beams with high diffraction efficiency while maintaining excellent uniformity. The hybrid algorithm combines the advantages of the mixed-region amplitude freedom (MRAF) algorithm and the overcompensation (OC) algorithm. The MRAF is firstly employed to achieve high diffraction efficiency. Subsequently, the OC algorithm is adopted to optimize uniformity. In addition, a more convenient convolution-based method is used to construct the descending edge of the target flat-top beam. A series of polygonal flat-top beams, such as triangular, square, pentagonal, and hexagonal, are obtained, and comparisons with the original methods are also carried out by means of simulations and experiments. Our experimental data demonstrate that an average diffraction efficiency above 97% is achieved.