Unlike any typical microscope AFM does not depend on electromagnetic radiation, it is a form of mechanical imaging of the surface topography with a sharpened probe (it has less than 50nm in diameter) where our data illustrates 3 dimensional representation of analyzed object. Probe moves across the surface being very close to it and detecting any changes (differences in the surface: different materials for example) or detecting physical features present on the surface. Largest area of the scan is square with dimensions: 100µm x 100µm.
Probe is attached to the cantilever. There is a laser light reflecting from the cantilever and when probe interacts with the sample, cantilever bends what results in change of the path of light. The output of laser is focused on the backside of a cantilever and reflected into photo detector with two sections. When probe which is located at the end of the cantilever interacts with the surface cantilever bends changing reflection of the laser light. These changes are recognized by photo detector and sent to the feedback controller.
In order to control the motion of the probe piezoelectric crystals are used. Many other devices which need precision at the nano or micro scale use piezoelectric crystals in order to achieve that type of precise movement. Piezoelectric materials change their shape as voltage potential is applied to the bottom or top part of the crystal, whereas their volume remains the same.
Atomic Force Microscopy was one of the fundamental steps in NanoScience. Creators Gerd Binning and Heinrich Rohrer received a Nobel Prize and researchers of the very small could finally see unseenable. Nanoobjects are often smaller than the length of the visible light, therefore traditional optical microscope methods would be useless; for example we would not see a 40nm difference in height using even the most sophisticated optical microscope. However , AFM offers chance for everyone to analyze objects with the most precision and ease of use. When data is acquired one might use free analysis software: “Gwyddion”, which lets users create beautiful and colorful representations of the obtained data.