Effect of spatial coherence on determining the topological charge of a vortex beam

Abstract

It is known that one can determine the topological charge of a vortex beam based on the Fourier transform of its intensity. We demonstrate both theoretically and experimentally that this method will be invalid for determining the topological charge of a vortex beam with low coherence. Furthermore, we propose a method to determine the topological charge of a vortex beam with low coherence based on its complex degree of coherence.