Number 203 (Story #1), November 17, 1994 by Phillip F. Schewe and Ben Stein LIGHT EMISSION IS MAPPED WITH ATOMIC RESOLUTION. The old rule that optical microscopy cannot achieve a spatial resolution much better than the wavelength of the light used can be surmounted by positioning the light source very close to the sample. Such "near-field" microscopes have in the past few years achieved lateral resolutions of 30 angstroms. Scientists at the University of Lausanne and IBM Zurich in Switzerland have now done better than that. They use a scanning tunneling microscope (STM) to image the gold surface; the sample was mounted at such an angle to the STM probe as to present a sort of grating, with a periodicity of 8.16 angstroms. But while they acquire a topographical record of the gold surface, the Swiss physicists also use the STM probe tip to induce the emission of photons from the surface atoms. This light is detected by a photomultiplier. Because the light emission is so sensitive to the tip- sample interaction and because the position of the tip can be controlled with picometer precision, the resultant "photon map" of the gold surface (or at least a one-dimensional slice) has an atomic resolution comparable to the STM topographical map. (R. Berndt et al., Physical Review Letters, 2 Jan. 95)