High-Speed AFM and Applications to Biomolecular Systems: Supplemental Video 1

A supplemental video from the 2013 review by Toshio Ando, Takayuki Uchihashi, and Noriyuki Kodera, "High-Speed AFM and Applications to Biomolecular Systems," from the Annual Review of Biophysics.

Principle of tapping mode AFM. The cantilever is oscillated in the z-direction at its resonant frequency. The position of the laser beam reflected back from the cantilever is monitored to measure the cantilever deflection. The oscillation amplitude reduced by tip tapping on the sample surface is maintained constant by moving the sample stage in the z-direction through feedback control. The resulting sample stage movement traces the sample surface. Therefore, the sample surface topography can be reconstructed by the use of a signal by which the z-scanner is driven.