What are the smallest objects ever photographed by an electron microscope?

[Realitycheck]

Is it at all feasible to get down to the quantum level?

[SkepticLance]

Depends what you mean by 'photographed'.

Normal photography needs light, and that has limitations. It is exceeded by electrons, which can be used in an electron microscope to photograph much smaller items, such as a small virus. However, if you extend your definition of 'photographed' further to mean 'detected and imaged', then we look at the scanning tunnelling microscope which can form images of individual atoms, though not their structure.

 

This may be called a bit of a cheat, since there is no direct image. Instead, the signal is translated by a computer, which forms the image on a screen.

[Realitycheck]

I meant "imaged". It seems that all of the images of atoms are reconstructed globs of art. Do we ever get to see an actual crude image, or must it simply be reconstructed into whatever image we want it to look like ?

[SkepticLance]

The stm does not really show what an atom looks like. That is probably a meaningless concept anyway. However, it does show how atoms are arranged with respect to each other. In my opinion, that is pretty damn cool.

[CharonY]

In general STMs or AFMs (both are scanning probe microscopy techniques, not EMs, and an AFM can easily be reconfigured to a STM, just as a sidenote) reach down to the submolecular level. At least in case of hard and/or conductive molecules. In theory you can measure the tunneling interaction with a single atom with a STM and these interaction signals are then converted into information, usually height, lateral resolution tends to be worse (depends on the piezo).

Now as mentioned by SkepticLance, all these techniques give you parameters of the atom/atom lattices, but there is no way to "see" anything, of course, within this size.

[Royston]

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