Production of annular flat-topped vortex beams

A model of an annular flat-topped vortex beam based on multi-Gaussian superimposition is proposed.We experimentally produce this beam with a computer-generated hologram(CGH) displayed on a spatial light modulator(SLM).The power of the beam is concentrated on a single-ring structure and has an extremely strong radial intensity gradient.This beam facilitates various applications ranging from Sisyphus atom cooling to micro-particle trapping.