Microscopy

There have been numerous variations on the types of microscopy outlined so far. A sampling of these is: acoustic microscopy, which involves the reflection of sound waves off a specimen; x-ray microscopy, which involves the transmission of x rays through the specimen; near field optical microscopy, which involves shining light through a small opening smaller than the wavelength of light; and atomic force microscopy, which is similar to scanning tunneling microscopy but can be applied to materials that are not electrically conducting, such as quartz.

An atomic force micrograph of the surface of a thin copolymer film. The atomic force microscope (AFM) is capable of atomic-scale resolution, and works by drawing a very fine probe across the surface of the sample. The vertical motion of the probe is converted into electronic signals which are then processed to give the type of surface map seen here. The advantage the AFM has over the scanning tunneling microscope is that it works for samples that are not electrical conductors. Photograph by Philippe Plailly. National Audubon Society Collection/Photo Researchers, Inc. Reproduced by permission.

One of the most amazing recent developments in microscopy involves the manipulation of individual atoms. Through a novel application of the STM, scientists at IBM were able to arrange individual atoms on a surface and spell out the letters "IBM." This has opened up new directions in microscopy, where the microscope is both an instrument with which to observe and to interact with microscopic objects. Future trends in microscopy will most likely probe features within the atom.