Abstract
We obtain general analytic expressions for the linear and angular momentum density of an elliptically polarized paraxial laser beam. As a partial case, we obtain expressions for the linear and angular momentum density of a paraxial elliptically polarized optical vortex. It is shown that for an arbitrary vortex field with rotational symmetry and with circular polarization the effect of the “angular tractor” takes place, which means that the flux of light energy rotates around the optical axis clockwise or counterclockwise at different radii in the beam cross section. It is also shown that the axial component of the angular momentum density of the vortex light field changes its sign at the same radii in the beam cross section. Microparticles trapped in the vortex Bessel beam at different radii are experimentally shown to rotate simultaneously clockwise and counterclockwise.
- Received 21 March 2018
DOI:https://doi.org/10.1103/PhysRevA.97.053833
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