Light Waves Brought to a Stop in a Crystal Promises New Ways to Control Photons

https://www.sciencealert.com/light-waves-brought-to-a-stop-in-a-crystal-promises-new-ways-to-control-photons

by Brajeshwar • 2 years ago

28 8 2 years ago

Perhaps it's impossible to explain this in an ELI5 manner (or even an ELI40+ manner), but as a layman I'm having a really hard time understanding what it means to "halt" a photon. For that matter, I'm having a hard time understanding how photons are slowed traversing through matter, but obviously I understand it's a common experience given that the speed of light in substances like glass or water is slower than a vacuum.

Just curious if anyone is able to recommend any sources that can help explain this to someone with a general knowledge of physics, but not a PhD in quantum mechanics.

mkw50532• 2 years ago

When light passes through a medium like glass or water, it interacts with the atoms and molecules in that material. This interaction involves the absorption and re-emission of the photons by the atoms, a process that takes time and thus effectively slows down the speed of light as it travels through the medium.

The research describes "photonic Landau levels." This is similar to how electrons are confined to certain energy levels when subjected to magnetic fields, but applied to photons. By confining photons to these levels, the crystal can effectively "trap" light in place. The light is still present and retains its energy, but it doesn't move forward; it's localized within a very small area of the crystal. The photons are not moving from one place to another as they normally would—they are caught in a sort of "light trap" created by the specific structural properties of the photonic crystal.

andersa• 2 years ago

Does the trapped light take up space, or can we use this to accumulate large amounts of energy like some kind of crystal-based battery?

eszed• 2 years ago

Is an individual photon sitting in place, or is it being absorbed and re-emited in sequence within a localised structure?

qup• 2 years ago

Well, given that I just read this story a couple days ago, I cannot miss the connection:

https://www.physics.utoronto.ca/~jharlow/slowglass.htm

It's about a 5-minute sci-fi read, incredibly on-topic, written in the 60s.

stinkyball• 2 years ago

Thankyou, great story :)

Light Waves Brought to a Stop in a Crystal Promises New Ways to Control Photons

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