Atoms in axially shifted tightly focused counter-propagating beams: the role of the Gouy and curvature phases

Abstract

We consider the interaction of atoms with two tightly focused and axially-shifted counter-propagating optical beams. At sub-wavelength focusing, we find that the scattering force potential in the threedimensional space between the shifted focal planes changes from a feature with a saddle-point to a three-dimensional trapping potential. Further analysis shows that due to the tight focusing, the trapping depends on significant contributions arising from the Gouy and curvature phase gradients of the interfering beams. The physics and its effects are illustrated with reference to the sub-wavelength trapping of sodium atoms.

Image processing of optical vortex and determination of OAM

“…The inhomogeneous characteristics of transverse profile of an optical vortex beam leads to the optical force gradient which can be used as a strong tool for manipulating some dielectric microparticles, atoms and molecules [10]. In theoretical point of view, Laguerre-Gaussian beams are well defined optical vortices which are the solutions of paraxial wave equation in cylindrical coordinates [11,12].…”