title: Optical spin-to-orbital angular momentum conversion in inhomogeneous anisotropic media.
abstract: We demonstrate experimentally an optical process in which the spin angular momentum carried by a circularly polarized light beam is converted into orbital angular momentum, leading to the generation of helical modes with a wave-front helicity controlled by the input polarization. This phenomenon requires the interaction of light with matter that is both optically inhomogeneous and anisotropic. The underlying physics is also associated with the so-called Pancharatnam-Berry geometrical phases involved in any inhomogeneous transformation of the optical polarization.
authors.affiliation: Dipartimento di Scienze Fisiche, Università di Napoli Federico II and CNR-INFM Coherentia Complesso di Monte S. Angelo, via Cintia, 80126 Napoli, Italy. lorenzo.marrucci@na.infn.it
authors.forename: L
authors.initials: L
authors.lastname: Marrucci
authors.forename: C
authors.initials: C
authors.lastname: Manzo
authors.forename: D
authors.initials: D
authors.lastname: Paparo