Atom-optics knife edge: Measuring narrow momentum distributions

By employing the equivalent of a knife-edge measurement for matter-waves, we are able to char- acterize ultra-low momentum widths. We measure a momentum width corresponding to an effective temperature of 0.9 ± 0.2 nK, limited only by our cooling performance. To achieve similar resolution using standard methods would require hundreds of milliseconds of expansion or Bragg beams with tens of Hz frequency stability.

Furthermore, we show evidence of tunneling in a 1D system when the “knife-edge” barrier is spatially thin. This method is a useful tool for atomic interferometry and for other areas in cold-atom physics where a robust and precise technique for characterizing the momentum distribution is crucial.

The article was published in: Physical Review A, Volume 98, Issue 2.

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This work was supported (in part) by the Fetzer Franklin Fund of the John E. Fetzer Memorial Trust.