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Awesome picture! Could someone explain to me how a DSLR camera can capture an image of a single atop? I thought atoms were very very small, like so small only
by VohuMana 9y ago
Awesome picture!
Could someone explain to me how a DSLR camera can capture an image of a single atop? I thought atoms were very very small, like so small only an electron microscope could "see" them. Maybe this device has been misrepresented and it is holding a small amount of atoms rather than a single one?
- dgritsko 9y agoFrom the article: > When illuminated by a laser of the right blue-violet color, the atom absorbs and re-emits light particles sufficiently quickly for an ordinary camera to capture it in a long exposure photograph.
- VohuMana 9y agoAh, missed that. Thanks :)
- excalibur 9y agoThat explanation doesn't really satisfy. Perhaps, based on a large body of experimental evidence, it is known that the number of atoms present can be determined by the apparent brightness. Perhaps it's something totally different. Regardless, it would be helpful if the author/photographer/somebody explained the rationale that makes them confident that this is only a single atom.
- ars 9y agoBasically the atom is glowing. Not very brightly, but enough so that the camera can see it. The human eye after all can see a single photon. A single atom can emit a single photon, so it's not such a stretch.
- ABCLAW 9y agoIsn't hard to figure out when you've only got one ion in the trap: https://www.physik.hu-berlin.de/de/nano/lehre/quantenoptik09/chapter13 https://www.physik.hu-berlin.de/de/nano/lehre/quantenoptik09... Heck, you can line up ions in a row and take pictures of those if you'd like.
- semi-extrinsic 9y ago> the rationale that makes them confident that this is only a single atom Nothing photographic, as I understand it. The atom is positively charged, and is suspended in ultra-high vacuum by electric fields. Effectively they're "weighing" it, by measuring the total charge of whatever is suspended, and knowing (from the ionization energy?) the charge on one atom. It should be noted that this is similar to how Millikan first measured the electron charge back in 1909.
- euyyn 9y agoThe article makes it sounds like the photographer already knew he could trap one atom, before taking the picture. My guess would be, as this is an electromagnetic trap, that two such ions would repel each other and the well is set to be shallow enough that at most one ion can remain inside.
- ajuc 9y agoThey only put 1 atom there, and it's in vacuum. It can't be anything else because of that :)
- joveian 9y agoI'm guessing there are at least two layers of glass between that atom and the sensor. Not really specific to this (excellent) picture, but I imagine that avoiding distortion due to the glass or smudges on the glass must be a huge part of high magnification photography. The whole light from a single atom part just makes it more amazing how clean and clear that window is...
- teekert 9y agoWhen blasting light in every direction, does it really matter how small the source is? As long as those photons hit your eye, you can see the object.
- matthewmcg 9y agoIn exactly the same way that a camera can take a photograph of a star, which (for all but the Sun) is an infinitesimally small point of light. As long as the light intensity is higher than the background noise, it will render as a smeared out blob[1] due to diffraction. [1] an Airy disk: https://en.wikipedia.org/wiki/Airy_disk https://en.wikipedia.org/wiki/Airy_disk