<title>Orbital angular momentum of mixed vortex beams</title>

Abstract

The orbital angular momentum (OAM) of the single vortex beam depends on its power and wavefront helicity. In the paper, this relation is generalized for mixed vortex beams composed of several coaxial vortices with different topological charges. The presented interference law indicates interference effects of the OAM resulting in local spatial gradients of the OAM density. Description of the OAM of mixed vortex beams is used for demonstration of a possibility to tune the OAM density of a composite vortex field without changing topological charges or intensity distribution. Experimental realization of the OAM tuning is discussed for interference of two focused vortex beams generated by means of a spiral phase mask.