title: Quantized rotation of atoms from photons with orbital angular momentum.
abstract: We demonstrate the coherent transfer of the orbital angular momentum of a photon to an atom in quantized units of variant Planck's over 2pi, using a 2-photon stimulated Raman process with Laguerre-Gaussian beams to generate an atomic vortex state in a Bose-Einstein condensate of sodium atoms. We show that the process is coherent by creating superpositions of different vortex states, where the relative phase between the states is determined by the relative phases of the optical fields. Furthermore, we create vortices of charge 2 by transferring to each atom the orbital angular momentum of two photons.
authors.affiliation: Atomic Physics Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8424, USA.
authors.forename: M F
authors.initials: MF
authors.lastname: Andersen
authors.forename: C
authors.initials: C
authors.lastname: Ryu
authors.forename: Pierre
authors.initials: P
authors.lastname: Cladé
authors.forename: Vasant
authors.initials: V
authors.lastname: Natarajan
authors.forename: A
authors.initials: A
authors.lastname: Vaziri
authors.forename: K
authors.initials: K
authors.lastname: Helmerson
authors.forename: W D
authors.initials: WD
authors.lastname: Phillips