We consider the optical dipole potential energy, which arises from the interaction of a two-level atom with a circularly polarized Laguerre-Gaussian laser beam of small waist. The beam is characterized by the existence of a longitudinal electric field component which is responsible for the appearance of a chiral term in the optical dipole potential energy. This term reverses sign if either the winding number or the wave polarization of the beam reverses sign. We propose a scheme of a bi-chromatic vortex interaction with the two-level atom in which the resulting optical dipole potential is fully chiral.

Here, we describe a systematic derivation of the general form of the optical helicity density of ellipticaly polarized paraxial Laguerre–Gaussian modes L G ℓ , p , σ . The treatment incorporates the contributions of the longitudinal field components for both the paraxial electric E and magnetic B fields, which satisfy Maxwell’s self-consistency condition in the sense that E is derivable from B and vice versa. Contributions to the helicity density to leading order in ( k 2 w 0 2 ) − 1 (where k is the axial wavenumber and w 0 the beam waist) include terms proportional to optical spin σ and topological charge ℓ , as well as a spin-orbit σ | ℓ | term. However, evaluations of the space integrals leading to the total helicity confirm that the space integral of the ℓ -dependent term in the density (which is due entirely to the longitudinal fields) vanishes identically for all ℓ and p , so that, in general, only σ determines the Hopf index, with the optical vortex L G ℓ p character featuring only in the action constant.

We show how optical Ferris wheel light fields can be exploited for the generation of internal-state-dependent optical lattices. We furthermore demonstrate how these lattices can be employed for the realization of controllable collisional gates. By employing realistic and experimentally accessible parameters, we demonstrate the potential of such gates, taking advantage of the extraordinary properties of optical Ferris wheels for efficient and scalable quantum computation.

We consider the creation of artificial gauge magnetic and electric fields created when a two-level atom interacts with an optical Ferris wheel light field. These fields have the spatial structure of the optical Ferris wheel field intensity profile. It is shown, we believe for first time, that when this optical field pattern is made to rotate, then we have the creation of artificial electromagnetic fields that propagate in curved paths. The properties as well the limitations of these artificial electromagnetic fields are investigated and discussed.

We study the generation of atom vortex beams in the case where a Bose-Einstein condensate, released from a trap and moving in free space, is diffracted from a properly tailored light mask with a spiral transverse profile. We show how such a diffraction scheme could lead to the production of an atomic Ferris wheel beam.