Fig. 2: Effects of a single light-pulse. | Nature Communications

Fig. 2: Effects of a single light-pulse.

From: Ultracold atom interferometry in space

Fig. 2

Depicted are the experimental observations (two upper panels) and theoretical simulations (lower panels) of the impact of a single light-pulse simultaneously inducing Bragg processes and phase imprinting on a matter-wave packet released from the trap in the low gravity environment of space (a) (left column), and on ground (b) (right column). Each picture shows the undiffracted and the diffracted parts due to Bragg and weak double-Bragg processes. In space, the striking feature is the amplitude modulation of all Bose-Einstein condensates along the y-direction which in our ground experiments was not visible, in accordance with our theoretical simulations. On ground, the free expansion time of the BECs was short (31 ms) to keep them in the Bragg beams and the focal region of the detection. In space, the longer expansion times (86 ms) lead to a larger fringe spacing which allows us to resolve the imprint. In addition, the phase imprinting due to the moving amplitude modulation vanishes on ground due to the Doppler shift caused by the larger detuning between the light beams A and B, resulting in a much larger velocity of the light pattern. In contrast to our model assuming a single BEC component, the experimental fringe patterns feature spatial distortions as well as a much lower contrast. The latter holds even in the case when only a segment of the picture along the y-direction (orange line) is analysed.

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