Optical forces on atoms subject to higher-order Poincaré vortex modes

Abstract

The interaction of atoms with higher-order Poincaré optical vortex modes of order $m\ge 0$ is explored for light close to resonance with atomic dipole transitions. It is well-known that atoms subject to optical vortex modes experience both translational and rotational forces acting on the atomic centre of mass, leading to atom dynamics and atom trapping. Here we consider the optical forces on atoms immersed in general paraxial higher-order Poincaré optical vector modes. The coupling to atoms gives rise to wide-ranging scenarios involving such modes in which any specific polarisation is within a spectrum of wave polarisation and all the interactions are treatable within a single formulation. We show that this gives rise to a variety of physical situations, governed by the mode order $m$, the polarisation represented by the angular coordinates of the mode on the surface of the unit Poincaré sphere, the atomic transitions involved, and their selection rules. We present the analytical steps leading to the optical forces on sodium atoms and display their variations in various situations.

10 pages, 5 figures

References in corpus (4)

• Realization of polarization evolution on higher-order Poincare sphere with metasurface
• Quadrupole absorption rate and orbital angular momentum transfer for atoms in optical vortices
• Quadrupole absorption rate for atoms in circularly-polarized optical vortices
• Absorption of hybrid fibre modes by Cs atoms in quadrupole transitions