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Small objects are usually hard to see because they scatter small amounts of light. In this case, the ion is illuminated with a laser close to a strong resonance
by fsh 7y ago
Small objects are usually hard to see because they scatter small amounts of light. In this case, the ion is illuminated with a laser close to a strong resonance which makes it emit a surprisingly large amount of light (tens of million photons per second). This makes it relatively easy for the camera to detect.
Atoms are about three orders of magnitude smaller than the wavelength of visible light. So for any optical microscope they are just point sources. The finite size spot a camera sees is only due to diffraction from the finite size of the objective. This is also why stars don't appear infinitely small in images.
- zaroth 7y agoFor those wondering about the word “objective” as it is used above; > In optical engineering, the objective is the optical element that gathers light from the object being observed and focuses the light rays to produce a real image. [1] I found this [2] article to be pretty approachable without the jargon overload like Wikipedia often suffers from. [1] - https://en.m.wikipedia.org/wiki/Objective_(optics) https://en.m.wikipedia.org/wiki/Objective_(optics) [2] - https://en.m.wikipedia.org/wiki/Diffraction-limited_system https://en.m.wikipedia.org/wiki/Diffraction-limited_system