MULTIPLE-BEAM ATOM INTERFEROMETER - THEORY AND EXPERIMENT

We first give a detailed account of the theory of atom interferometers based on a sequence of laser pulses projecting the atomic wave packet s onto a spatially separating dark superposition state. We then descri be the experimental realization of a multiple beam atom interferometer based on this method. In our experiment, we observe an interference s ignal that shows the sharply peaked Airy-function like pattern charact eristic for multiple beam interference. Besides this fringe sharpening effect, we observe a further significant difference compared to the s ignal of a conventional two-beam atom interferometer. When the time be tween the beamsplitting pulses is varied, we observe collapse and revi val of the fringe pattern, which is caused by a recoil phase shift inc reasing quadratically with the transverse atomic momentum.