Emerging beam resonances in atom diffraction from a reflection grating

TL;DR

This paper reports the first observation of emerging beam resonances in atom diffraction, showing anomalies at Rayleigh angles in helium atom reflection from a grating, linking classical wave-optical models to atom optics.

Contribution

It demonstrates emerging beam resonances in atom diffraction, extending the concept of Rayleigh-Wood anomalies from photons and electrons to atoms.

Findings

Anomalies observed at Rayleigh angles in atom diffraction.

Total reflectivity and diffraction intensities show characteristic anomalies.

Results align with classical wave-optical models of Rayleigh and Fano.

Abstract

We report on the observation of emerging beam resonances, well known as Rayleigh-Wood anomalies and threshold resonances in photon and electron diffraction, respectively, in an atom-optical diffraction experiment. Diffraction of He atom beams reflected from a blazed ruled grating at grazing incidence has been investigated. The total reflectivity of the grating as well as the intensities of the diffracted beams reveal anomalies at the Rayleigh angles of incidence, i.e., when another diffracted beam merges parallel to the grating surface. The observed anomalies are discussed in terms of the classical wave-optical model of Rayleigh and Fano.