COLLAPSE AND REVIVAL OF THE FRINGE PATTERN IN A MULTIPLE-BEAM ATOM INTERFEROMETER

We report on the observation of collapse and revival of the fringe pat tern in a multiple-beam atom interferometer, when the drift time betwe en the beam splitting processes is varied. The atomic beam splitters a re realized with laser pulses pumping the atoms into velocity selectiv e dark states. For small drift times, the interference signal shows th e sharply peaked Airy function-like pattern characteristic for multipl e-beam interference. The fringe pattern collapses for larger drift; ti mes due to a recoil phase shift increasing quadratically with the tran sverse atomic momentum. When the total interaction time reaches an int eger multiple of the inverse two-photon recoil energy in frequency uni ts, the original fringe pattern is revived.