HackerTube / Video
How big is a visible photon?
Huygens Optics
Huygens Optics shows through a laser interference experiment that the question of a photon's size is really about coherence length. It argues that photons exist as energy exchanges between radiation and matter, not as little particles in free space.
HN recommends it as an approachable, intuitive explanation of why visible photons can be surprisingly large, from a channel known for practical optics.
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