High efficiency preparation of single trapped atoms using blue detuned   light assisted collisions
  We report on a procedure by which we obtain a 91% loading efficiency of single 85Rb atoms in an optical microtrap. This can be achieved within a total preparation time of 542 ms. We employ blue detuned light assisted collisions to realize a process in which only one of the collision partners is lost. We explain the mechanism for efficiently loading a single atom and discuss the factors that limit the final efficiency. 
A. V. Carpentier, Y. H. Fung, P. Sompet, A. J. Hilliard, T. G. Walker,   and M. F. Andersen
physics.atom-ph quant-ph