I'm not quite sure what exactly the photo shows, and I couldn't figure it out from any of the pop-sci or meta-news that are floating around on the net (like this one in New Scientist - remind me to stop reading this magazine :P). It didn't sound like the reporters had understood the principle at all themselves. So I looked on the Max Planck Institute's homepage to get a slightly better explanation (in German), which says something completely different than the above article...


As far as I got it, it looks like this: The scientists create Near-IR Laser flashes that only contain one oscillation (2 peaks, one dip) of the EM field.
These flashes pass through a neon gas, exciting the neon atoms to release light in the extreme UV range. Because the laser pulse is so extremely short, we get exactly 3 releases, one for each maximum. The highest maximum is filtered out, sharpened by a stepped mirror and directed onto another neon probe. There, it passes through the IR Laser pulse from before.

That's where the German article stops - I'm not quite sure about how the experimental setup looks like for the imaging. NS said something about measuring the energy of the electrons, but in the German versions electrons are only involved in creating the second pulse. Does anyone have a better explanation?

And I'm still not entirely sure what I'm seeing. Which direction is the pulse travelling in in the picture? What size scale are we looking at (the German article said something about 100 million photons in the UV pulse) and what are the smaller wave structures inside the "oscillation"?
And how did they figure out the 80 attoseconds? Is that before or after the sharpening?


Can anybody explain or post a link to a better description? I have taken photonics in University but I don't claim to understand enough of it to figure out the rest of it from the information I have.

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[Foot mouth in put]
Si tacuisses, philosophus mansisses.

There, I reminded you :wink:

I'm confused too, but from the German language article you linked to, it seems that the investigators hope to follow how electrons move in materials.

I agree that at the very least, they should include ordinary snapshots of the apparatus, so that we can try to figure out what their Fig. 1 shows.

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Chris Hillman

Read these PF posts. Avoid Wikipedia--- except for these versions. Read this and this suggested sticky. When asked for advice, I always say: never take advice!

Whoa! I wonder if this method can be used in the LHC (or the RHIC, Fermilab, etc)!

That would be an interesting image...

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I came for the astronomy but I do love the physics!