We report improved precision measurements of the van der Waals potential strength (C3) for Na atoms and a silicon-nitride (SiNx) surface. We studied diffraction from nanofabricated gratings with a particular "magic" open fraction that allows us to determine C3 without the need for separate measurements of the width of the grating openings. Therefore, finding the magic open fraction improves the precision of C3 measurements. The same effect is demonstrated for a grating with an arbitrary open fraction by rotating it to a particular "magic" angle, yielding C3 =3.42±0.19 eV 3 for Na and a SiNx surface. This precision is sufficient to detect a change in C3 due to a thin metal coating on the grating surface. We discuss the contribution to C3 of core electrons and edge effects.
|Original language||English (US)|
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|State||Published - Dec 18 2009|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics