Generation of "perfect" petal beams using spatial light modulator

Abstract

For the first time, to the best of our knowledge, "perfect" petal beams (PPBs) are experimentally generated and characterized. Our method involves the implementation of the superposition of two beams with opposite topological charges m multiplied by an annular slit function. By simply controlling the phase of the input beam in the spatial light modulator, we test beams with varying radii and varying thicknesses for different values of m. For a given constant initial waist of the beam, we find that, unlike the conventional petal beams, PPBs have a ring radius which is independent of the m encoded in it, a feature it shares with a perfect vortex beam. Further, we observe that alongside the prominent mirror-symmetrical petal-like structures are artifacts which may be due to the interference of the diffracted petal-like structures. Nonetheless, the contrast of the produced beams defined as the ratio between the spread and the sum of the minimum and maximum intensities is equal to unity. This means that we can still distinguish the primary lobes from the minima in the intensity distribution with precision.