He-atom diffraction from nanostructure transmission gratings: The role of imperfections - art. no. 033608

The relative diffraction peak intensities of He atoms with an incident beam energy of 65 meV diffracted from a microfabricated 100 nm-period transmiss ion grating are analyzed using both Fresnel anti Fraunhofer diffraction the ory. The projected slit width could be varied from 50 nm down to less than 1 nm by inclining the grating at angles up to Theta(0) = 42 degrees with re spect to the incident beam. Good agreement between calculated and measured peak intensities, up to the sixth order, is obtained by accounting for rand om deviations in the slit positions, and averaging over the velocity spread of the incident beam as well as the spatial extent of the nozzle beam sour er. It is demonstrated that He atom beam diffraction together with simple t ransmission measurements is an excellent means of characterizing such grati ngs including a detailed determination of the slit width, the bar shape, an d random as well as periodic disorder.