Yu. B. Ovchinnikov

Generation of a hollow laser beam for atom trapping using an axicon

Abstract We demonstrate a simple method to produce a hollow laser beam for applications in atom trapping using an axicon. We obtain a beam profile having the shape of a ring with a diameter of ∼800 μm and a width of 35 μm. In a large dark inner region, the intensity is only 0.1% of the peak intensity. The properties of the hollow beam are very promising for atom traps based on the optical dipole force.

Gravitational laser trap for atoms with evanescent-wave cooling.

Abstract We propose a trap based on an evanescent light wave formed on the surface of a pyramidal hollow in a glass substrate. Alkali atoms repeatedly reflected at the evanescent wave and kept in their lower hyperfine ground state by a weak repumping laser beam can be cooled to recoil-limited temperatures by a Sisyphus and a geometric cooling mechanism, which are connected with spontaneous transitions to the upper hyperfine ground state during the reflections. Numerical simulations for 39K, 85Rb and 133Cs predict equilibrium 3D rms momenta of ∼3.5 h k . We estimate the collisional loss rates and show that the trap can produce extremely cold and dense samples of atoms and may even reach the point of Bose-Einstein condensation.

Laser guiding of atoms in a hollow optical fiber

Abstract The laser guiding of atoms in a hollow optical fiber is discussed. Our estimates show that for reasonable laser power 1W, the use of atomic guidance in an optical waveguide allows an atomic flow to be transmitted without any substantial loss over a distance of about ten meters.

Coherent beam splitter for atoms based on a bichromatic standing light wave.

We propose a new coherent atomic beam splitter that is based on the induced redistribution of photons in the intense field of two collinear standing waves with different frequencies. In the dressed-atom approach, we show that this scheme can provide a clear large-angle splitting into two components without being restricted to the Raman-Nath regime.

Channeling of atoms in a standing spherical light wave

One-dimensional localization of sodium atoms in a standing spherical light wave has been observed. The atoms have an oscillatory motion with an amplitude of approximately lambda/10 along the nodes (or loops) of the wave.

Reflection cooling of sodium atoms in an evanescent light wave

Abstract Studied in this work is the cooling of a beam of sodium atoms upon its reflection from an evanescent light wave. The cooling mechanism is associated with the spontaneous transitions of the atoms between the hyperfine-structure sublevels of the ground state. Subject to studies is the relationship between the reflection angle of the atoms and the frequency detuning and intensity of the light wave. It is demonstrated experimentally that the transverse atomic momentum component can be reduced by more than one half ( Δp⊥ p⊥ ≅ 0.5 ) in a single reflection event, the number of cooled atoms in the reflected beam exceeding 50%. It should be noted that the loss of atoms in reflection can be made as small as desired, and so the reflection cooling cycle can be repeated many times over.

Dipole force rectification in a monochromatic laser field

Abstract We propose a novel scheme which allows to generate a strong rectified dipole force in a simple monochromatic laser field. A basic example demonstrates that this optical force can act on atoms with a Zeeman-split transition in the field of two counterpropagating intense laser beams with different polarization.

Sub-Doppler manifestation of the magneto-optical radiation force

Abstract We consider a novel manifestation of the magneto-optical radiation force for an optical transition with a ground-state magnetic substructure. The force originates from optical Zeeman-pumping in close relation to polarization cooling with linearly polarized light and, at low optical saturation, exhibits sub-Doppler dependnece on the atomic velocity. We show that, in an inhomogeneous magnetic field, the radiation force an be used for the magneto-optical trapping of ultracold atoms.

Rectified dipole force in a bichromatic standing light wave

Abstract Theoretical and experimental studies on the properties of the radiation force acting on two-level atoms in a bichromatic standing light wave are reported. It is shown that on an atom at rest a rectified gradient force is exerted having a great magnitude (≈4 h kγ observed in the experiment) in combination with a macroscopic spatial period (≈10cm). The dependence of the force on the atomic velocity is investigated.

Observation of the Magneto-Optical Radiation Force by Laser Spectroscopy

We report on the experimental investigation of the stimulated magneto-optical radiation force using a laser-spectroscopic method, where we detect the effect of the atom-field interaction on the transmitted laser light. The results both demonstrate the applicability of this new method and confirm all basic properties expected for the novel force from theory.