Interferometer Ramsey-Borde

A Mach-Zehnder atom interferometer is not the only atom interferometer that could be used. One could also use a Ramsey-Borde interferometer [12] to test neutrality of atoms. The capacitor should then be set where trajectories are parallel and atoms are in the same internal state in both paths, so that the phase shift depends only on atomic charge. A possible disadvantage of these interferometers is that the observed contrast is around 20 % according to [12] and that many atoms of the source are lost in extra interferometers also present in the apparatus. 

The very first demonstration of molecule interference dates back to the days of Estermann and Stern [Estermann 1930] who demonstrated experimentally diffraction of 11-2 at a LiF crystal surface in 1930. Further experiments with diatomic molecules had to await progress and interest in atom optics. A Ramsey-Borde interferometer was realized for the iodine dimer in 1994 [Borde 1994] and was recently used [Lisdat 2000] with K. Similarly, a Mach-Zehnder interferometer was demonstrated [Chapman 1995 (a)] for Na2. The nearfield analog to the Mach-Zehnder interferometer, a Talbot-Lau interferometer, was recently applied to experiments with L12 [Berman 1997], Diffraction at nanofabricated gratings also turned out to be the most effective way to prove the existence of weakly bound helium dimer [Schollkopf 1996] and to measure its binding energy [Grisenti 2000],... 

F. Riehle, Th. Kisteers, A. White, J. Helmecke, Ch.J. Borde Optical Ramsey spectroscopy in a rotating frame Sagnac effect in a matter-wave interferometer. Phys. Rev. Lett. 67, 177 (1991)... 

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