I Viewing light at four trillion frames per second

  • Thread starter zincshow
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These researchers appear to be imaging a pulse of light travelling at the speed of light. Unfortunately, the detail is behind a paywall. Why does the light appear to pulse bright to dark over about a 5ps timeframe?
The are not viewing a light beam, they are viewing the scattered light as the beam travels through a material. I'd guess that the scattering is variable based on the characteristics of the material.

Wrichik Basu

Gold Member
2018 Award
The article under discussion has been published in Phys. Rev. Lett. From the news article by APS, the caption of the video says:
In this 33-picosecond clip produced with the new technique, a light pulse (red blob) travels through a transparent solid. Upon reaching the edge of the material (dashed line), the pulse travels invisibly through air, hits a mirror, and then re-enters the material.
(Emphasis added)

The reference to the paper (for future visitors, in case the link is unavailable) is:
Yu Lu et al., Compressed Ultrafast Spectral-Temporal Photography, Phys. Rev. Lett. 122, 193904 – Published 17 May 2019
In what seems to be a similar technique, this YouTube clip makes it easier to appreciate the making of such "light speed" imagery as reflections from within a plastic water bottle (diluted with a trace of milk) track the movement of a laser pulse.


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