Vortex beam shaping

摘要

A novel method for tuning the orbital angular momentum (OAM) content of a vortex beam is presented. This approach makes use of the shaping of the odd and even components of the helical phase profile associated to the vortex. A relative azimuthal shift of the components results in the harmonic variation of the magnitude of the OAM density of the beam. We calculate the OAM content and show that for a beam with a vortex of topological charge m, the OAM per photon per unit length can be tuned continuously from 0 to mh. We also observe the experimental propagation of the beam and compare the propagation parameters to our theoretical predictions.