Topological charge and orbital angular momentum of optical signals with asymmetric optical vortices

摘要

Here, we derive theoretically the topological charge (TC) of several vortex laser beams without the circular symmetry, namely asymmetric Laguerre-Gaussian (LG), asymmetric Bessel-Gaussian (BG), and asymmetric Kummer beams. Although such beams are obtained as superposition of respective conventional LG, BG, and Kummer beams, these beams have the same TC equal to that of a single mode, n. The induced asymmetry affects the normalized orbital angular momentum (OAM) of all these beams, and what is more, it affects the OAM of different beams differently. However, whatever the asymmetry degree, TC of the beams remains unchanged and equals n. Theoretical findings are validated via numerical simulation.