OBSERVATION OF LIGHT-INDUCED COHERENCE LOSS IN A CESIUM ATOMIC FOUNTAIN

We report on an experimental measurement of the phase shifts associate d with the AC Stark effect. The optically induced light shift was meas ured using a Ramsey fringe technique and we have made detailed studies of the potential sources of coherence loss that can occur for an atom ic sample manipulated by light. Pie investigated the loss of coherence due to the light shifts induced by using a non-uniform laser beam and the effects of scattered light. These measurements have implications for experiments which use optical techniques for manipulating atomic w avepackets in atom optics and atom interferometry.