Imaging and focusing of atoms by a fresnel zone plate

Focusing of and imaging with atoms by means of a spherical Fresnel zone plate has been observed for the first time. An intense beam of metastable helium atoms with atomic de Broglie wavelength ₃₁=0. 5--2. 5 is passed through either a single or a double slip with dimensions in the 10- range. This transverse intensity distribution is imaged by a Fresnel zone plate, 210 in diameter and with an innermost zone diameter of 18. 76. For ₃₁=1. 96 the focal length is 0. 45 m. The imaging properties of the zone plate are presented and compared with numerical calculations.