Rotating windmill array beam with adjustable wing angle

In this study, we introduce a method for adjusting the wing angles of windmill beams. After varying the phase parameters, the sector strengths with different wing angles were generated, and they exhibited a self-rotating property in free-space propagation. This phase was obtained by performing an elliptical operation on the stretching vortex phase. The angle between the wings of the beam varied with the ellipticity. Accordingly, array windmill beams with adjustable wing angles were designed. Finally, we analyzed the evolution of the wing angle and self-rotating properties of the beam in detail. The experimental results were consistent with those of simulations. This operational method can be applied to optical cropping techniques, and the beam can be used in optical manipulation and imaging applications.