S. B. Cahn

Atom interference in pulsed standing-wave fields

We have studied suboptical wavelength atomic gratings, generated by the interference of atomic de Broglie waves in a time-domain interferometer. Three short optical standing- wave pulses, detuned from resonance with a cloud of approximately 100 (mu) K85 Rb atoms, act as phase gratings for atomic matter waves. The first two standing- wave pulses, separated by time T, produce a sequence of atomic density gratings of periods

Phase-space imaging of trapped atoms using magnetic sublevel coherence

lamda/4 at time 1.5T after the first pulse. The dependence of our signals on the time separation of the pulses is in good agreement with our theoretical predictions. As far as we know, this is the first time when the formation of a high order matter-wave diffraction grating was observed in real time. This demonstrated ability to produce sub-wavelength structures makes our techniques applicable to atomic beam lithography.

Collisional revival of magnetic grating free-induction decay

Experimental results on phase-space imaging of a laser- cooled atomic cloud are presented. Both position and velocity information are encoded in the frequency of the signal coherently radiated from the cloud. This encoding is achieved by application of a position-dependent magnetic field. Fourier transformation of the signal yields a projection of the phase-space density of the atoms. Since the projection direction is determined by the imposed field gradient, we can reconstruct the phase-space structure of the cloud and trace its time evolution.

Phase Space Diagnostics of Trapped Atoms By Magnetic Ground-State Manipulation

Summary form only given. A ground-state coherence grating involving the magnetic sublevels of the F=3 ground state in /sup 85/Rb is created in Doppler-broadened vapor using an excitation pulse that consists of two traveling waves with orthogonally polarized wave vectors. The decay of the grating that is due to thermal motion is probed by a traveling-wave readout pulse. This results in a scattered signal magnetic grating free-induction decay (MGFID) that is detected using a heterodyne technique. In our experiment, collisional revival can be expected when the mean free path is less than the grating spacing.