Until 2006, the resolution of imaging systems based on atomic beams was not better than that of an optical microscope, mainly due to the poor performance of the focusing elements. Such elements use small numerical aperture ; usually, atomic mirrors use grazing incidence, and the reflectivity drops drastically with increase of the grazing angle; for efficient normal reflection, atoms should be ultracold, and dealing with such atoms usually involves magnetic, magneto-optical or optical traps.