cool.
Is that a description of what a scanning electron microscope does? or have they moved on from those?
Well, electron microscopy is a yet another technique, different from both standard light microscopy (the normal microscopes we’d use in school) and AFM (atomic force microscopy), the method that’s described in the paper. Actually, electron microscopy is probably closer to traditional light microscopy than it is to AFM.
It’s a really crude analogy, but AFM is almost like that old fable about the group of blind guys who touch an elephant and variously describe it as a snake (if one touches the tail) or a tree limb (if one touches the trunk) or a sheet (if one touches the ear), etc. Except in AFM, *all* those “touches” are recorded and graphed over a two-dimensional plot, so you get the “whole elephant”, and not just one bit.
In both EM and light microscopy, you’re getting info by the interaction of high energy particles (EM) or energy-rich photons (light microscopy) with the target in question. It’s just that when things get small enough (like individual molecules), the wavelengths of visible light aren’t short enough to do you any good in terms of building an image.
Where scanning EM is like AFM is that in both you are progressively moving a probe (your beam of electrons or your molecular “record needle”) in a systematic fashion across the target object.