title: Optical Polarization Möbius Strips and Points of Purely Transverse Spin Density.
abstract: Tightly focused light beams can exhibit complex and versatile structured electric field distributions. The local field may spin around any axis including a transverse axis perpendicular to the beams' propagation direction. At certain focal positions, the corresponding local polarization ellipse can even degenerate into a perfect circle, representing a point of circular polarization or C point. We consider the most fundamental case of a linearly polarized Gaussian beam, where-upon tight focusing-those C points created by transversely spinning fields can form the center of 3D optical polarization topologies when choosing the plane of observation appropriately. Because of the high symmetry of the focal field, these polarization topologies exhibit nontrivial structures similar to Möbius strips. We use a direct physical measure to find C points with an arbitrarily oriented spinning axis of the electric field and experimentally investigate the fully three-dimensional polarization topologies surrounding these C points by exploiting an amplitude and phase reconstruction technique.
authors.affiliation: Max Planck Institute for the Science of Light, Guenther-Scharowsky-Straße 1, D-91058 Erlangen, Germany.|Institute of Optics, Information and Photonics, University Erlangen-Nuremberg, Staudtstraße 7/B2, D-91058 Erlangen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bauer
authors.affiliation: Max Planck Institute for the Science of Light, Guenther-Scharowsky-Straße 1, D-91058 Erlangen, Germany.|Institute of Optics, Information and Photonics, University Erlangen-Nuremberg, Staudtstraße 7/B2, D-91058 Erlangen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Neugebauer
authors.affiliation: Max Planck Institute for the Science of Light, Guenther-Scharowsky-Straße 1, D-91058 Erlangen, Germany.|Institute of Optics, Information and Photonics, University Erlangen-Nuremberg, Staudtstraße 7/B2, D-91058 Erlangen, Germany.|Department of Physics, University of Ottawa, 25 Templeton, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Gerd
authors.initials: G
authors.lastname: Leuchs
authors.affiliation: Max Planck Institute for the Science of Light, Guenther-Scharowsky-Straße 1, D-91058 Erlangen, Germany.|Institute of Optics, Information and Photonics, University Erlangen-Nuremberg, Staudtstraße 7/B2, D-91058 Erlangen, Germany.|Department of Physics, University of Ottawa, 25 Templeton, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Peter
authors.initials: P
authors.lastname: Banzer