COLLECTIVE ATOMIC DYNAMICS IN A MAGNETOOPTICAL TRAP

We have experimentally studied the dynamics of rubidium atoms in a magneto-optical trap employing optical sigma+ sigma--molasses with controlled time phase differences in a vapour cell. We find that the action of radiation pressure vortices gives rise to a novel long-range interaction between the atoms which may explain the irregular atomic-density distributions possible in such traps even at perfect alignment. We have also recorded absorption spectra of trapped low-density atomic samples which include time-phase-dependent narrow Raman and Rayleigh resonances.