Analytical description of optical vortices generated by discretized vortex-producing lenses

RUMI, GONZALO; ACTIS, DANIEL; AMAYA, DAFNE; GÓMEZ, JORGE A.; RUEDA, EDGAR; LENCINA, ALBERTO

Physical Review A

American Physical Society

Año: 2018 vol. 97

2469-9926

In this article, a general analytical treatment (any topological charge?any number of discretization levels)for the diffraction of a Gaussian beam through a discretized vortex-producing lens is presented. In the proposal,the field is expressed as a sum of Kummer beams with different amplitudes and topological charges, which arefocalized at different planes on the propagation axis. Likewise, it is demonstrated that characteristics of diffractedlight can be modified by tuning the parameters of the setup. Vortex lines are analyzed to understand the internalmechanism of measurable topological charges that appear in specific planes, apparently violating topologicalcharge conservation. Conservation of the topological charge is verified and theoretical predictions are supportedby experiments.