 |
Scanning tunneling microscope: In the original AFM built in 1985 a
scanning tunneling microscope tip
was use to measure the motion of
a cantilever. Although this technique
was viable, implementation and
operation was very difficult. |
 |
Interferometer: A Michelson interferometer can be adapted to measure the deflection of a cantilever in an AFM. Although very sensitive, the interferometer
was not successful because of fringe hopping. That is, the probe could jump between interference fringes while scanning. |
 |
Crystal Oscillator: A piezoelectric
quartz crystal such as quartz can be
used to measure the force between
a probe and a surface. If the probe
mounted on the crystal is vibrated
and positioned close to a surface, the
interaction of the probe and surface
will cause a change in the vibration.
This change is proportional to force. |
 |
Piezo-resistive Cantilevers: A
cantilever can be fabricated that has
a small piezo-resitive element in it that
changes resistance if the cantilever
bends. This type of sensor is viable,
but very difficult to manufacture in
appropriate quantities. |
 |
Fiber Guide: Light may be transmitted
down a fiber optic and reflected off a
cantilever into another fiber optic. If
the surface is close enough to the
fiber optics, then the amount of light
that is collected by the second fiber
optic depends on the distance from
the fiber optic to the cantilever. |
