Number 228 (Story #2), May 31, 1995 by Phillip F. Schewe and Ben Stein IMAGING WITH AN ATOMIC BEAM has been accomplished by physicists at the University of Hanover in Germany. Past efforts to use focused atoms as an imaging source have been hampered by the velocity-spread of the beam particles, which results in a long focal length and considerable aberration. In the Hanover experiment, laser-cooled, polarized cesium atoms are used to image a patterned mask with varying degrees of magnification. Those atoms transmitted through the mask are focused by a hexapole magnet, which tugs at the atoms' magnetic dipole moments. Further downstream, at a designated image plane, the atoms are made to fluoresce by exposing them to laser light. The resultant image is recorded by a video camera. The researchers expect that if a solid substrate were positioned at the image plane then this whole process could be used as a sort of "slide projector" for casting images of patterns, in the form of deposited atoms, onto the substrate. The technique may therefore be useful in sub-micron lithography. (W.G. Kaenders et al., Nature, 18 May 1995.)