title: Circularly polarized beams and vortex generation in uniaxial media.
abstract: We deduce the expressions for the two circularly polarized components of a paraxial beam propagating along the optical axis of a uniaxial crystal. We find that each of them is the sum of two contributions, the first being a free field and the second describing the interaction with the opposite component. Moreover, we expand both components as a superposition of vortices of any order, thus obtaining a complete physical picture of the interaction dynamics. Consequently, we argue that a left-hand circularly polarized incoming beam, endowed with a circular symmetric profile, gives rise, inside the crystal, to a right-hand circularly polarized vortex of order 2. The efficiency of this vortex generation is investigated by means of a power exchange analysis. The Gaussian case is fully discussed, showing the relevant features of the vortex generation.
authors.affiliation: Dipartimento di Fisica, Università Roma Tre, and Istituto Nazionale di Fisica della Materia Unità di Roma 3, Rome, Italy. ciattoni@fis.uniroma3.it
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ciattoni
authors.forename: Gabriella
authors.initials: G
authors.lastname: Cincotti
authors.forename: Claudio
authors.initials: C
authors.lastname: Palma