February 14, 2018 10:16 AM   Subscribe

The overall winner of the 2018 Engineering and Physical Sciences Research Council science photography competition is 'Single Atom In An Ion Trap'. More winners.
posted by fearfulsymmetry (11 comments total) 15 users marked this as a favorite
I love that there is essentially no difference between the atom photo and the Carl Sagan pale blue dot photo
posted by NoMich at 10:51 AM on February 14, 2018 [4 favorites]

It very much seems as if that atom was not in any way "visible to the naked eye" unless the eye in question was a DSLR camera taking long-exposure shots, or maybe the eyes of one of those frogs that are said to be able to see single photons. I do wonder how much illumination it would take to make it as visible to the naked eye as it is to the camera. More than would be reasonable, or enough to vaporise everything in the area?

The image of the photograph is nicely visible, and lovely.
posted by sfenders at 11:12 AM on February 14, 2018 [1 favorite]

When we're talking about single-atom object, "illumination" doesn't work in a traditional photographic sense. You're dealing with inelastic scattering and photon field absorption/emission instead.

What happens is this: the incident laser pumps the electron cloud around the atom to an excited state, very simplistically expanding the orbital radius of the electrons (this is a fictional analogy). After some time, the electron cloud reverts back to its ground state, the fictional orbit contracts again, which shoots out a photon. This emitted photon is characteristic of a certain allowed decay, meaning that it always has the same energy and so the same colour.

So this isn't a "picture" of the atom in the sense that we're not seeing light reflecting off of a physical structure (those ideas don't make much sense at this scale anyway). What it is is the light characteristic of a particular atomic emission "line".

Another way of looking at this: we're seeing the light of a single-atom star. This is an impressive accomplishment, both in conception and execution, especially given the (relatively) modest equipment.
posted by bonehead at 11:25 AM on February 14, 2018 [24 favorites]

You're dealing with inelastic scattering and photon field absorption/emission instead.

Sounds like an ex.
posted by Brandon Blatcher at 12:06 PM on February 14, 2018

Doing a little noodling about, this appears to be either the Sr+ line at 460.733 nm or the Sr++ line at 407.771 nm. The image looks more blueish to me than purple, so I'd make a wild guess that it's the singly-charged ion, not the doubly-charged one. Maybe someone with a better monitor and eyesight than me could say though---it's been a few decades since I did this sort of thing.
posted by bonehead at 12:09 PM on February 14, 2018

Another way of looking at this: we're seeing the light of a single-atom star.
I was wondering about the amount of energy being pumped into that atom. I was thinking it was more like a supernova, at least compared with the resting state of the atom.
posted by CheeseDigestsAll at 12:56 PM on February 14, 2018

> So this isn't a "picture" of the atom

Weeell. I'd say that this kind of interaction is at least part of how we end up seeing objects... Only happening billions of times, and mostly with atoms that are part of complex molecules etc... But many of the photons that reach our eyes were not emitted by the sun, right?
posted by kleinsteradikaleminderheit at 2:29 PM on February 14, 2018

Sure, but this isn't the same way a reflective surface works, for example. We see most objects with reflective light, and their colours depend on the light which isn't absorbed by the surface. A reddish apple absorbs/does not reflect most colours except for the red ones, for example, so apples look red. This isn't, in that respect, the same as most photographs of objects---taken with a light source and reflected light off the object.

We see this is by a different mechanism, the (laser-stimulated) emission of light. It's an active light source, not a passive one.
posted by bonehead at 2:54 PM on February 14, 2018

The idea that instead of the traditional light-reflecting-off-of-a-physical-structure we are instead seeing “the light of a single atom star” is very beautiful. My enjoyment is enhanced. Thank you.
posted by lazaruslong at 5:48 PM on February 14, 2018 [1 favorite]

wait am i missing something that explains why the post is titled "science photogorahy"?
posted by numaner at 9:24 PM on February 14, 2018

I get what you are getting at, but if we classify based on that then what happens to astrophotography? Are we seeing "pictures" of stars?

Regardless, I like this way more than "pictures" of atoms taken with electron microscopes. I would feel differently if my own organic eyes worked like electron microscopes I guess.
posted by Index Librorum Prohibitorum at 11:17 PM on February 14, 2018

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