This article was wonderful. We have had light and electron microscopes. Can we look forward to atom-wave microscopes?

Bill Schindele
Thousand Oaks, Calif.

Yes. A team led by Bodil Holst at Graz University of Technology in Austria has built a microscope that bombards a sample with helium waves and then measures how the waves reflect to create a picture. In late 2007, Holst’s team took the first-ever two-dimensional picture with a helium atom microscope: a blurry image of a tiny, honeycomb-shaped grating. —Ewen Callaway