Atomic fountain Ramsey spectroscopy

Once the kinetic energy has been reduced to a few raK, the earth s gravitational field could be used to further slow the atoms in an atomic "fountain," so that the projectiles can be observed for extended periods in free fall near the turning point of their parabolic trajectories. Optical two-photon Ramsey spectroscopy of such freely falling atoms is possible with a single standing wave laser field which the atoms traverse on their way up and again on their way down (Fig. 9). >25 as in ordinary Ramsey... 

Fig. 9. Scheme for optical Ramsey spectroscopy of an atomic fountain.24,25... 

R.G. Beausoleil, T.W. Hansch Ultra-high-resolution two-photon optical Ramsey spectroscopy of an atomic fountain. Phys. Rev. A 33, 1661 (1986)... 

R.G. Beausoieil, T.W. Hansch Ultra-high-resolution two-photon optical Ramsey spectroscopy of an atomic fountain. Phys. Rev. A 33, 1661 (1986) M. A. Kasevich, E. Riis, S. Chu, R.G. DeVoe RF spectroscopy in an atomic fountain. Phys. Rev. Lett. 63, 612 (1989)... 

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