Cooling of atoms on reflection from a surface light wave

D. V. Laryushin, Yu. B. Ovchinnikov, V. I. Balykin +1 more

T. A. Vartanyan

D. V. Laqushin, Yu. B. Ovchinnikov, V. I. Balykin

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 hyperflne-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 (A p I/p I = 0.5) . 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.

S. Altshuler, Lee M. Frantz, Rubin Braunstein

I. Manek, U. Moslener, M. Hammes +1 more

Summary form only given. The gravito-optical surface trap (GOST) confines cesium atoms by a blue-detuned repulsive evanescent wave (EW) in combination with gravity. Horizontal confinement is provided by the conservative optical dipole potential of a hollow, cylindrical laser beam, far blue-detuned from resonance. For preparing a very cold and dense cesium gas in the GOST, we use evanescent wave 'Sisyphus' cooling, which is based on inelastic reflections of the atoms from the EW. Using this method we have obtained a temperature of 3 /spl mu/K, which corresponds to an average distance of the atoms from the surface of 19 /spl mu/m. As a very important feature for attaining very high densities, EW cooling allows one to keep the atoms predominantly in the absolute ground state, thus avoiding trap loss by light assisted collisions.

M. Ia. Amusia, A. S. Baltenkov