If we're seeing the single photon emitted by a single atom, then how much larger is the spot of light in the image compared to the atom that emitted it?
Why isn't there a ruler somewhere in the picture? My brain is absolutely failing to make sense of the scales and sizes in this image.
> then how much larger is the spot of light in the image compared to the atom that emitted it?
The atom is about 255 picometers, the light is around 400 nanometers. That makes the light around 1500 times larger than the atom.
(Which also helps explain why visible light can not distinguish atoms placed close together - it's so much larger than them.)
> Why isn't there a ruler somewhere in the picture? My brain is absolutely failing to make sense of the scales and sizes in this image.
The two electrodes are about 2mm apart. About the width (not length) of a sesame seed. It's really small. The photo was taken through a microscope.
Another point of reference: the width between the electrodes is about 5,000 times the wavelength of the light being emitted.
In theory, if you had a good enough camera, the dot of light would be around 1/5000 of the width. (However the diffraction limit of your lens might enter into play, blurring the image.)
And finally, the width between the electrodes is about 8,000,000 times the size of the atom.
Why isn't there a ruler somewhere in the picture? My brain is absolutely failing to make sense of the scales and sizes in this image.