Phasor analysis of atom diffraction from a rotated material grating

The strength of an atom-surface interaction is determined by studying atom diffraction from a rotated material grating. A phasor diagram is developed to interpret why diffraction orders are never completely suppressed when a complex transmission function due to the van der Waals interaction is present. We also show that atom-surface interactions can produce asymmetric diffraction patterns. Our conceptual discussion is supported by experimental observations with a sodium atom beam.