Experiment on Matter wave self-Imaging in pulsed optical standing wave field*

In this Paper we report a non-Raman-Nath regime diffraction of a condensate by an optical standing wave. We demonstrate atomic CM motion-based bidirectional, high-order matter-wave self-imaging and condensate momentum oscillation. We emphasize that this phenomenon exists in the non-Raman-Nath regime that is also far away from typical Bragg regime, where the atomic CM motion plays a key role. We further note that the matter-wave self-imaging effect reported here is very different from the temporal matter-wave Talbot effect reported previously. To the best of our knowledge, such a full matter-wave self-imaging due to CM motion has never been demonstrated before. We consider a system of two electronic states and n momentum states, and take numerical simulation of the diffraction probabilities for the first few significant diffraction orders. It shows that at $\tau _P \approx 23\mu {\kern 1pt}s$ the zeroth-order diffraction probability is near 100{\%} whereas all high orders are very small. This approximately agrees with the observed time of $\tau _P =25\mu {\kern 1pt}s$ when all n $\ge $ 1 orders are very small.