By Tunde Eso
In 1981, Gerd Binnig and Heinrich Rohrer developed the scanning tunneling microscope, transcending the limits of optical microscopes.
In optical microscopes, the observable size of objects is limited by the wavelength of light. The scanning tunneling microscope solved this limitation.
The instrument has an extremely thin point, which passes very close to a surface. A low electrical charge is positioned between this point and the surface. Through the tunnel effect – a quantum mechanical effect – a current arises that varies with the distance from the surface. This current allows an image to form where objects as small as individual atoms can be distinguished.
Five years after revealing their new microscope, Binnig and Rohrer were awarded the 1986 Nobel Prize in Physics "for their design of the scanning tunneling microscope." They shared the award with Ernst Ruska.
Learn more about their research by reading their paper 'Surface Studies by Scanning Tunneling Microscopy' that was published on this day in 1982:https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.49.57