Reconstructing the Poynting vector skew angle and wavefront of optical vortex beams via two-channel moiré deflectometery

A novel approach based on the two-channel moire ́ deflectometry has been used to measure both wave-front and transverse component of the Poynting vector of an optical vortex beam. Generated vortex beam by the q-plate, an inhomogeneous liquid crystal cell, has been analyzed with such technique. The measured topological charge of generated beams are in an excellent agreement with theoretical prediction. c © 2013 Optical Society of America OCIS codes: 050.4865, 010.7350, 120.4120, 260.6042. It is well-understood that optical beams may possess two rotational like degrees of freedom corresponding to vector and phase features of the light that are known as a spin and orbital angular momentum [1]. A beam with circular polarization possesses spin angular momentum (SAM) of ± ~ per photon, which sign is defined by the polarization handedness. In contrast, orbital angular momentum (OAM) is associated with helical phase-front of the beam. The optical field is proportional to exp (i`φ) and carries ` ~ angular momentum per photo