Effect of attractive atom-surface interaction on emerging beam resonances

Abstract

We study how the attractive atom-surface interaction affects emerging beam resonances in atom optics. Emerging beam resonances (Rayleigh-Wood anomalies in optics) occur, in general, in diffractive systems at Rayleigh conditions where a new spectral order emerges from a periodic surface [1]. The resonance effect causes abrupt intensity changes of the other diffraction beams. We investigate quantum reflection of helium atoms scattering off various square-wave gratings. As the ratio of grating period to strip width increases, which changes the landscape of the atom-surface interaction potential above the grating, drastic changes of the diffraction intensities are observed at Rayleigh conditions. The distinct variations occurring in this simple system can serve as a test bench for quantitative theoretical models of emerging beam resonances.