Open AccessAngular momentum density of a circularly polarized paraxial optical vortex
Author(s) -
V. V. Kotlyar,
A. A. Kovalev
Publication year - 2018
Publication title -
kompʹûternaâ optika
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.491
H-Index - 29
eISSN - 2412-6179
pISSN - 0134-2452
DOI - 10.18287/2412-6179-2018-42-1-5-12
Subject(s) - physics , angular momentum , optical vortex , circular polarization , vortex , paraxial approximation , optics , clockwise , angular momentum of light , polarization (electrochemistry) , light beam , orbital angular momentum of light , total angular momentum quantum number , orbital angular momentum multiplexing , beam (structure) , optical axis , rotational symmetry , angular momentum coupling , classical mechanics , mechanics , amplitude , chemistry , microstrip , lens (geology)
We obtain general analytic expressions for the angular momentum density of a vectorial circularly polarized paraxial optical vortex. It is shown that for any vortex field with the rotational symmetry and circular polarization, an effect of the “angular tractor” takes place, which means that the flow of light energy rotates around the optical axis clockwise or counter-clockwise at different radii in the beam cross section. It is also shown that on the circles of these radii in the beam cross section, the axial component of the angular momentum density of the vortex light field changes its sign. Thus, microparticles trapped in the vortex beam at different radii will rotate either clockwise or counterclockwise.