Geometrical characterization of nondiffracting beams: geometric optical current and geometric vorticity for Bessel beams

摘要

Nondiffracting beams have the particular property that their time averaged intensity profile does not change when it is measured in every plane normal to the direction of evolution of the beam. Starting from Durnin's solution for the scalar wave equation, we study and characterize nondiffracting beams geometrically. We find that optical scalars describe the behavior for the light rays determining the beam, meanwhile the caustic encodes information of the optical current and the vorticity for these kind of beams. We obtain the geometric optical current and the geometric vorticity for Bessel beams, using only information provided by its geometric characterization.