Researchers at Ulsan National Institute of Science and Technology (UNIST), in Korea, and Fritz-Haber-Institut der Max-Planck-Gesellschaft, in Germany, have recently conducted a study investigating matter-wave diffraction from a periodic array of half planes. Their paper, published on Physical Review Letters (PRL), reports on the reflection and diffraction of He and D2 beams from square-wave gratings of a 400−μm period and strip widths ranging from 10 to 200 μm at grazing-incidence conditions.