Vortices from wavefront tilts

We show evolution of optical vortices in the regions of a wavefront where circulating phase gradients are present. Two different regions in a wavefront are given different tilts and it is shown that phase singularities can evolve at discrete points along the line of phase discontinuity. The phase distribution and the gradient in the neighborhood of these points are studied. Using a spatial light modulator (SLM) we have experimentally demonstrated the vortex generation.