Beam Shaping for Phase Singularities

In this paper we are molding the phase profile of a Gaussian beam in order to achieve a phase singularity called optical vortex. For this purpose, we apply the beam shaping technique for a 635 nm wavelength radiation using a diffractive optical element with high diffractive efficiency. We use reflective spiral phase plates and fork-like computer generated holograms, fabricated with photolithographic processes and electron beam lithography, respectively. Uniform ring intensity is achieved in the optical vortex configurations and also zero intensity where the phase is undefined. Phase singularities interferences are done using a Michelson interferometer. Beam shaping simulations results based on the Kirchhoff integral are in concordance with experimental results.