Quantum physicist David Nadlinger from the University of Oxford managed to capture an image that would have been impossible only a few years ago: a single atom suspended in an electric field viewable by the naked eye. The amazing shot titled “Single Atom in an Ion Trap” recently won the overall prize in the UK’s Engineering and Physical Sciences Research Council (EPSRC) science photo and imaging contest. You can see the atom in the shot above, the tiny speck at the very center.
To be clear, the photo doesn’t capture just the atom, but rather light emitted from it while in an excited state.
If you can't see it, here it is zoomed in a bit.
In which case, it's no longer "visible to the naked eye"...but you know, the other photo was a photo and therefore not the naked eye, either, so whatever. Still pretty cool, I think.
More info here, if you're curious.