Towards realization of an atomic de Broglie microscope:: Helium atom focusing using fresnel zone plates

A neutral, ground-state, He-4 atom beam has been focused using Fresnel zone plates. At only moderate demagnification (0.40X), a focused spot diameter of less than or equal to 2.0 mu m is achieved at a signal intensity of 500 counts/s. This is an improvement over previous work by a factor of 10 in resolution, 10(3) in signal intensity, and 10(8) in focused beam density, and allows the full intrinsic intensity profile of a focused atomic Fresnel spot to be measured for the first time. Raster scans of 15 and 25 mu m wide slits across the focused spot demonstrate transmission scanning helium de Broglie microscopy of micron resolution.