title: Generation of light carrying orbital angular momentum via induced coherence grating in cold atoms.
abstract: We report on the generation of light carrying orbital angular momentum through Bragg diffraction into an electromagnetically induced coherence grating in a degenerate two-level system of cold cesium atoms. The induced Zeeman coherence grating is shown to contain the spatial phase structure of the incident beams. The exchange of phase information between a light beam with orbital angular momentum and a long-lived atomic coherence opens up the way to process quantum information encoded in a multidimensional state space.
authors.affiliation: Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife-PE, Brazil.
authors.forename: S
authors.initials: S
authors.lastname: Barreiro
authors.forename: J W R
authors.initials: JW
authors.lastname: Tabosa