Kim Lee Yeong, Lee Ju Hyeon, Kim Yun-Tae, Park Sanghwan, Lee Chang Young, Schöllkopf Wieland, Zhao Bum Suk
Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea.
Phys Chem Chem Phys. 2021 Apr 7;23(13):8030-8036. doi: 10.1039/d0cp05694d. Epub 2021 Feb 15.
We report on an experimental test of Babinet's principle in quantum reflection of an atom beam from diffraction gratings. The He beam is reflected and diffracted from a square-wave grating at near grazing-incidence conditions. According to Babinet's principle the diffraction peak intensities (except for the specular-reflected beam) are expected to be identical for any pair of gratings of complementary geometry. We observe conditions where Babinet's principle holds and also where it fails. Our data indicate breakdown conditions when either the incident or a diffracted beam propagates close to the grating surface. At these conditions, the incident or the diffracted He beam is strongly affected by the dispersive interaction between the atoms and the grating surface. Babinet's principle is also found to break down, when the complementary grating pair shows a large asymmetry in the strip widths. For very small strip widths, edge diffraction from half planes becomes dominant, whereas for the complementary wide strips the atom-surface interactions leads to a strong reduction of all non-specular diffraction peak intensities.
我们报告了在原子束从衍射光栅的量子反射中对巴比涅原理的一项实验测试。氦束在近掠入射条件下从方波光栅反射和衍射。根据巴比涅原理，对于任何一对具有互补几何形状的光栅，衍射峰强度（镜面反射光束除外）预计是相同的。我们观察到了巴比涅原理成立的情况以及它失效的情况。我们的数据表明，当入射光束或衍射光束靠近光栅表面传播时会出现失效条件。在这些条件下，入射或衍射的氦束会受到原子与光栅表面之间色散相互作用的强烈影响。当互补光栅对在条带宽度上表现出很大的不对称性时，也会发现巴比涅原理失效。对于非常小的条带宽度，来自半平面的边缘衍射占主导，而对于互补的宽条带，原子 - 表面相互作用会导致所有非镜面衍射峰强度大幅降低。
