“…Due to the widespread technological applications in manipulating small macroscopic particles [32], the cooling and trapping of neutral atoms [33], Bose-Einstein condensates [34], driving micro fabricated gears for creating micrometre-scale motors [35] and so on, there has been increasing interest in the generation of optical vortex which has helical wavefront and undefined phase at an isolated zero amplitude point in recent years. Several methods for generating optical vortex have been reported, including the use of computer generated holograms [36], geometric mode converters [37,38], spatial light modulators (SLM) [39][40][41], and spiral phase plates [42][43][44]. Here we suggest a method using liquid crystal spatial SLM to generate the optical vortex with the requirement given in Eq.…”