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A laser pointer at 2B FPS [video]

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615 points thunderbong | 1 comments | 19 Oct 25 06:42 UTC | HN request time: 0.204s | source
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MostlyStable ◴[20 Oct 25 22:18 UTC] No.45650133[source]▶
As I understand it, this is sort of simulating what it would be like to capture this, by recreating the laser pulse and capturing different phases of it each time, then assembling them; so what is represented in the final composite is not a single pulse of the laser beam.

Would an upgraded version of this that was actually capable of capturing the progress of a single laser pulse through the smoke be a way of getting around the one-way speed of light limitation [0]? It seems like if you could measure the pulse's propagation in one direction, and the other (as measured by when it scatters of the smoke at various positions in both directions), this seems like it would get around it?

But it's been a while since I read an explanation for why we have the one-way limitation in the first place, so I could be forgetting something.

[0] https://en.wikipedia.org/wiki/One-way_speed_of_light

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1. ajnin ◴[21 Oct 25 00:32 UTC] No.45651129[source]▶
No, as he explains in the video, this is not a stroboscopic technique, the camera _does_ capture at 2 billion fps. But it is only a single pixel! He actually scans the scene horizontally then vertically and sends a pulse then captures pixel by pixel.