title: Split in phase singularities of an optical vortex by off-axis diffraction through a simple circular aperture.
abstract: Diffraction patterns of an optical vortex through several shaped apertures reveal its topological charge. In this Letter, we theoretically and experimentally show that diffraction of a Laguerre Gaussian beam through a circular aperture at an off-axis position can be used to determine the magnitude and sign of the topological charge. To our knowledge, this is the first time that a simple circular aperture has been used to detect orbital angular momentum of an incident optical vortex.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Taira
authors.forename: Shukui
authors.initials: S
authors.lastname: Zhang