Atomic force microscope

The atomic force microscope consists of a cantilever with a sharp tip at its end. The tip is brought into close proximity of a sample surface. The force interaction between the tip and the sample leads according to Hook's law to a deflection of the cantilever. The deflection is measured and (in most cases) a feedback mechanism is employed to adjust the tip to sample distance to keep the cantilever deflection and thus the force between the tip and the sample constant. The tip is then scanned across the sample surface and the vertical displacement s necessary to maintain a constant force on the tip is recorded. The resulting map of s(x,y) represents the topography of the sample.