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How big is a visible photon?

Huygens Optics · 792.7K views · 2021-07-05 · 20:34

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Overview

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.

On Hacker News

HN recommends it as an approachable, intuitive explanation of why visible photons can be surprisingly large, from a channel known for practical optics.

Recommended by 3 HN people across 3 months · HN mentions 2021–2025

Topics

Quantum physicsEveryday physics & science demos
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photonscoherence lengthinterferenceopticsquantum

What people said

somat · 2023-01 · Recommendation

I am not a physicist but fun fact, In transit there is no such thing as a photon(electro magnetic waves can transit at any energy level) however light can only interact with matter at discrete energy levels, so the photon(a discrete energy level of light) only exists there, at the interaction with matter. For some very good practical optics you can do a lot worse than the Huygens Optics youtube channel. [VIDEO]

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jiggawatts · 2022-08 · Recommendation

I know it's not exactly Nature, but I like this one for the approachable and intuitive explanation: [VIDEO] Fundamentally, you have to believe in nonsense such as kilometer-sized particles that are also infinitesimal if your point of view is that photons are particles. Many of the "mysteries" of Quantum Mechanics vanish if keep in the back of your mind that QM is just a bag of mathematical tricks that "work" in specific scenarios to solve practical problems, but aren't a model of "what actually occurs". Practically all of it is restricted to statistical predictions related to matter. Remove matter or remove statistics and then the models are no longer valid. I'm not making this up. Go dig up any of the original QM papers and these assumptions and/or constraints are called out in the first few paragraphs.

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NavinF · 2022-03 · Recommendation

Yeah I was also surprised to find that photons can be really big: [VIDEO] Before I saw the experiments in that video, I assumed photons were about as wide as their wavelength.

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Sources

Video by Huygens Optics, played through YouTube.

Data and selection notes

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