(a) A new polarimetric system consists of polarizer P, Wollaston prism , and a circular wedge compensator . This setup produces a table of all polarization states. When working in reverse direction (light incident on circular wedge compensator ), the optical vortex appears as shown (as a phase map) in part (b). Having the position of this vortex point, it is easy to read the polarization state of the incident light; (c) a more complex system named “spatial elliptical polariscope”. Here M is a birefirngent medium under measurement. Figure (d) shows the intensity distribution with two dark points where optical vortices are seeded. Each vortex points (white points) indicate the state of the polarization of fast and slow beams, respectively. The black points show the position of maximum intensity. The distribution of these points enable determining the azimuth and ellipticity of both the beams and also the retardation between them [36].
