title: Sagnac interferometer method for synthesis of fractional polarization vortices.
abstract: We present a method for producing laser beams of nonuniform polarization where the polarization direction rotates on a trajectory about the beam propagation direction. Our method uses a Sagnac interferometer that incorporates a spatial light modulator to combine beams that possess oppositely charged phase vortices in order to achieve the desired polarization vortex. We demonstrate the utility of our method by producing polarization vortices characterized by a fractional index, and we compare the results with calculations of the expected fields.
authors.affiliation: Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, UK. philip.jones@ucl.ac.uk
authors.forename: P H
authors.initials: PH
authors.lastname: Jones
authors.forename: M
authors.initials: M
authors.lastname: Rashid
authors.forename: M
authors.initials: M
authors.lastname: Makita
authors.forename: O M
authors.initials: OM
authors.lastname: Maragò