Generation of optical vortices by using spiral phase plates made of polarization dependent devices.

A method to construct spiral phase plates (SPPs) from quarter-wave plates and spatially variable half-wave plates (SVHWPs) is proposed. Optical vortices were experimentally generated by using SPPs made of polarization-dependent devices. The topological charge of the optical vortex can be also determined by the structure of the SVHWP and the polarization of the incident beam.