Towards Realization of an Atomic de Broglie Microscope: Helium Atom Focusing Using Fresnel Zone Plates
A neutral, ground-state, 4He atom beam has been focused using Fresnel zone plates. At only moderate demagnification \(0.40×\), a focused spot diameter of <=2.0 μm is achieved at a signal intensity of 500 counts/s. This is an improvement over previous work by a factor of 10 in resolution, 103 in signal intensity, and 108 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 μm wide slits across the focused spot demonstrate transmission scanning helium de Broglie microscopy of micron resolution.