Orbital angular momentum and topological charge in shaped optical vortex beams

Laguerre-Gauss and Bessel beams with optical vortices (OV) have been extensively used in applied areas as quantum communications [1], optical tweezers [2] and plasmonics [3]. Such beams have degenerate topological charge (TC) and orbital angular momentum (OAM), which are distinct physical quantities. In this work we present a general approach for experimentally characterizing OAM and TC in OV [4]. Using the definition of the local OAM [4,5] it is discussed how the information of the TC and the OAM can be obtained for shaped OV with various azimuthal phase dependencies. It is then shown that OAM and TC may be distinguished in OV with cores shaped like a line, a corner, or a triangle pattern.