A scanning probe microscope (SPM) is any type of microscope that can see surfaces on a very fine scale--so fine, in fact, that individual atoms may be discerned. There are several types of SPMs, all about the size of a fingernail, but all rely on a small, extremely sharp probe that scans across a surface, recording the forces it encounters and transmitting this information back to a sensor. With such microscopes scientists have studied surfaces at the level of individual atoms.

There are three basic types of scanning probe microscopes, all of which work slightly differently: (1) the atomic force microscope (AFM), (2) the scanning tunneling microscope (STM), and (3) the near-field scanning optical microscope (NSOM). The first scanning probe microscope was an STM, invented in 1982 by Heinrich Rohrer and Gerd Bining of the IBM Zurich Research Center in Switzerland. In 1986 Binnig and Rohrer shared the Nobel...