Spatial localization and accumulation of neutral atoms by the light-induced drift effect

Nicholas Sullivan, Shira Jackson, ByungChan Ha +1 more

I. V. Krasnov

Abstract A novel mechanism of the formation of a deep optical superlattice (OSL) for three-dimensional (3D) trapping of resonant impurity atoms immersed in a transparent cold buffer gas is proposed and investigated theoretically. This mechanism is associated with the joint action of two factors of different physical nature: rectification effect of the gradient force of light pressure and effect of the light induced drift (LID) of atoms (a consequence of the difference in gas-kinetic cross sections of excited and unexcited atoms). Such a situation can be realised when a gas mixture is irradiated by a bichromatic combined light beam which is a special coaxial superposition of cosine-Gaussian optical beams. Here, the RcGF creates a periodic 1D array of deep potential wells (OSL) along the beam axes, and an effective force, causing LID, pulls resonant particles into the combined light beam and provides their transverse (with respect to the beam axes) confinement in OSL. As a result, there can occur a giant accumulation of impurity particles in the OSL cells, accompanied by a strong spatial particle localization far away from the walls of the reservoir, in which the gas mixture is located.

T. P. Reďko

H. G. C. Werij, J. P. Woerdman

Jeffrey A. Kleinfeld, Alan D. Streater

Light-controlled deposition of potassium atoms onto a glass surface by light-induced drift (LID) is demonstrated. The collection of atoms by wave-front curvature is found to be important for maximizing the deposition rate. The light control of diffusive deposition is demonstrated by using LID to push atoms away from surface regions where a layer is not wanted. The measured spatial resolution of this process in the experiment was about 100 μm. Pressure and intensity effects on both deposition processes are discussed.

Rupamanjari Ghosh, Sushanta Dattagupta, J. Singh

Light-induced drift of optically active atoms in a buffer gas is a consequence of the unequal diffusive frictions suffered by the excited and the ground-state atoms. This drift can be used to create an ``optical piston,'' in which the active atoms are pushed forward by light through the semipermeable membrane of the buffer gas. Normally, optical piston effect is studied when the active atoms are neutral in a confined one-dimensional situation. We present a detailed theory of this phenomenon when the active atoms are charged and a magnetic field is applied for ``tuning'' the direction as well as the magnitude of the drift, thus removing the necessity of confinement. Our study is in different geometries of the light beam and the magnetic field, first in the weak collision model, and then for the strong collision and the Boltzmann-Lorentz models.