Emerging beam effects in out-of-plane grating diffraction of He atom beams

Abstract

We report on emerging beam resonances appearing in diffraction patterns of a helium atom beam reflected at grazing incidence from a grating. The plane ruled grating is mounted in an out-of-plane diffraction configuration. We present the measured angular diffraction patterns as a function of the atom's energy change along the grating normal. This presentation allows us to readily trace back the peak positions and widths to the geometry of the out-of-plane diffraction configuration. In the diffraction patterns, an interference effect due to emerging beam resonances is found to progress side by side with a new emerging diffraction beam.