Producing optical vortices through forked holographic grating: study of polarization

Abstract

It is important to know what happens to initial polarization during the formation of optical vortices. We use a computer-generated forked holographic grating to produce optical vortices in the laboratory and study changes in polarization, introduced by the grating, which generates optical vortices in its diffracted orders. The Mueller matrix has been used to quantify changes in the polarization in diffracted orders containing optical vortices. Decomposition of the Mueller matrices estimates the polarizing properties, such as diattenuation, retardance and depolarization of the system. We find that the system is a non-depolarizing system. The study also shows that spin and the orbital angular momentum of photons are not coupled in this process.