How do you look at a molecule? It's not so hard with an electron microscope--but getting a good look with the optical scanning type can be devilishly difficult. The problem: The optical "signature" of the molecule is masked by the huge volume of surrounding haze. That haziness can be minimized by focusing the probe beam more tightly. But the focus of conventional lenses just isn't tight enough. Researchers at AT&T Bell Laboratories say they have solved that problem with a new kind of microscope that funnels light through an optical fiber that tapers to 100 billionths of a meter, or one-thousandth the width of a human hair.
The Bell Labs researchers, Eric Betzig and Rob Chichester, reported in the issue of Science due out on Nov. 26 that they used their "near-field" scanning optical microscope to identify single molecules with more than 100 times the sensitivity of any previous method. The system allows them to generate a precise map of individual molecules on the surface of a specimen. Bell Labs sees a wide range of uses for the technology in cell biology, analytical chemistry, genetics, and in the new field of molecular engineering, which involves building electrical and mechanical devices out of individual molecules. Last year, Bell Labs announced that it used near-field imaging technology with a fiber to store data almost 100 times as densely as commercial optical-storage systems.