Darmstadt 2008 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
Q: Fachverband Quantenoptik und Photonik
Q 45: Materiewellenoptik
Q 45.2: Vortrag
Donnerstag, 13. März 2008, 14:15–14:30, 3G
Diffraction of helium atom beams from a micro-structured reflection grating — •Bum Suk Zhao1, Stephan Schulz2, Gerard Meijer1, and Wieland Schöllkopf1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany — 2Universität Ulm, Institut für Quanteninformationsverarbeitung, Albert-Einstein-Allee 11, 89069 Ulm, Germany
We have observed high-resolution diffraction patterns of a thermal-energy helium-atom beam reflected from a micro-structured surface grating at grazing incidence. The grating has a periodicity of 20 µm and consists of 10-µm-wide Cr stripes patterned on a quartz substrate. Fully-resolved diffraction peaks up to the 7-th order are observed at grazing incidence angles up to 20 mrad. With changes in de Broglie wavelength or incidence angle the relative diffraction intensities show significant variations which are attributed to the atom-surface Casimir-van der Waals potential. In addition, the overall probability of coherent reflection is found to increase with increasing de Broglie wavelength and decreasing incidence angle. We discuss whether this behavior indicates quantum reflection at the long-range attractive branch of the atom-surface potential.