Physicists Create Time-Reversed Waves of Optical Light

Re:Physicists Create Time-Reversed Waves of Optical Light by ta1234567890 on Friday December 18, 2020 @01:09AM (#25464363)

> We have found a way to precisely measure where all that scattered light arrives and at what times, then create a 'backwards' version of that light, and send it back through the fog

I'm assuming this is just a sort of analogy, because unless the fog was somehow frozen in time, there's no way the light would (de)scatter in the same way going backwards, it just wouldn't be hitting the same spots within the fog. Now, if they are able to predict the exact flow of the fog, that would be incredibly impressive.

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Re:Physicists Create Time-Reversed Waves of Optical Light by semi-extrinsic on Friday December 18, 2020 @02:03AM (#25464570)

I think the scattering medium is indeed assumed to be frozen in time. This would be the case for any solid of course, but also for a sufficiently homogeneous fog. I assume you are only inverting the statistical average of the scattering medium properties, so as long as those are frozen in time it's sufficient.

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Re:Physicists Create Time-Reversed Waves of Optical Light by Gravityloss on Friday December 18, 2020 @05:16AM (#25465676)

Maybe the fog droplets move slowly compared to light? Don't know if that's true.

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