Consistent isolation of individual atoms using cold collisions

The fact that a single neutral atom stored in an optical micro-trap is very well isolated from the environment makes it attractive for application in a quantum logic device. Scaling such a device requires a consistent and efficient method of loading a single atom into the micro-trap. By inducing light-assisted collisions between trapped pairs of atoms we observe the outcome of individual collision events. This allowed us to devise a method that enables a loading efficiency of 83% of a single atom into a micro-trap. Furthermore, we are able to accurately count the small number of atoms using fluorescence imaging at high densities while minimizing loss through light assisted collisions.