We demonstrate two atom interferometric schemes based on Kapitza-Dirac scattering in a magnetic trap. In the first method, two Kapitza-Dirac scattering pulses are applied with a small time delay between them. High contrast interference is observed both using a thermal cloud and a Bose-Einstein condensate (BEC). In the second method, two Kapitza-Dirac scattering pulses are applied to a BEC with a time separation sufficiently large that the interfering orders complete half an oscillation in the magnetic trap; this enables interferometry between spatially separated paths.

We study superfluorescence ͑SF͒ from spherical and cigar-shaped clouds of laser-cooled Rubidium atoms from the 5D 5/2 level through the 6P 3/2 level to the 5S 1/2 ground level. The atomic system is initially excited to the 5D 5/2 level from the ground state via two-photon excitation through the intermediate 5P 3/2 level. The fluorescence on the 6P-5S transition at 420 nm is recorded using time-resolved measurements. The time delays of the observed SF emission peaks typically scale as ϳN −1 , where N is the atom number, and are much smaller than the time delay expected for uncorrelated cascade fluorescence. Since N is significantly smaller than the threshold number for SF on the 420 nm transition, and larger than the threshold number for the 5D-6P transition at 5.2 m, our observations suggest that the 420 nm SF emission is triggered by rapid deexcitation of the 5D to the 6P level via SF at 5.2 m. The observed SF time delays for 420 nm emission agree with SF time-delay estimates for the 5.2 m transition. For spherical clouds, the SF is isotropic. For cigar-shaped clouds, the SF is highly anisotropic. Along the long axis of cigar-shaped atom clouds, SF and incoherent cascade fluorescence produce temporally well-resolved peaks in the detected signal. In this case, the SF component of the signal is highly concentrated along a direction in between the directions of the two almost parallel excitation beams. The observed SF intensities scale as N, suggesting that the 5D level is regeneratively pumped during the SF decay.

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We demonstrate laser cooling in an optical lattice that employs Raman transitions. Four laser beams with different frequencies form a one-dimensional lattice with a basic lattice period that is a factor of 2 less than in standard optical lattices. Rb atoms are cooled to 8 K. We measure the intensity-and detuning-dependence of the cooling mechanism. Our experimental results agree well with theoretical models.