Non-conservation of topological charge: experiment with optical vortex

Non-conservation of topological charge is demonstrated using an optical vortex. An asymmetrical vortex of charge one is produced with a computer-generated hologram and a cylindrical lens. It is shown experimentally and theoretically that the propagation of such a vortex, produced in almost all practical systems, violates the conservation of topological charge. Control parameters have been found for the system, which leads to this violation. The vortex and topological charge being generic to any wave field, nonconservation of topological charge can have important implications, starting from particle physics to cosmology and optical soliton collisions to many applications in biology based on optical vortices.