Quantum reflection of helium atom beams from a microstructured grating

TL;DR

This study demonstrates quantum reflection of helium atom beams from a microstructured grating, revealing detailed diffraction patterns and insights into atom-surface interactions at grazing incidence.

Contribution

It provides high-resolution diffraction data showing quantum reflection effects on a microstructured surface, advancing understanding of atom-surface potentials.

Findings

Resolved diffraction peaks up to 7th order

Significant variation in diffraction intensities with wavelength and angle

Quantum reflection explained by Casimir-van der Waals potential

Abstract

We observe high-resolution diffraction patterns of a thermal-energy helium-atom beam reflected from a microstructured surface grating at grazing incidence. The grating consists of 10-$\mu$m-wide Cr strips patterned on a quartz substrate and has a periodicity of 20 $\mu$m. Fully-resolved diffraction peaks up to the $7^{\rm th}$ order are observed at grazing angles up to 20 mrad. With changes in de Broglie wavelength or grazing angle the relative diffraction intensities show significant variations which shed light on the nature of the atom-surface interaction potential. The observations are explained in terms of quantum reflection at the long-range attractive Casimir-van der Waals potential.