Fastest-Ever Flashgun Captures Image of Light Wave

loconet writes to tell us that a team of researchers have created the shortest-ever flash of light. Weighing in at just 80 attoseconds, this flash has already been used to capture an image of a laser pulse and could possibly be used in the future to capture the electron movement around large atoms.

Comments

Re:Sounds impossible

[bugnuts]

from TFA, I believe it's imaging a laser pulse shot through neon gas. It's the laser pulse that triggered the flash in the first place.

Bizarrely, the article states

As each flash is intense enough to completely ionise a neon atom and release an electron, the researchers could use those electrons like a flashgun, to illuminate some of the original 2.5 femtosecond trigger pulses of laser light. This is interesting, because the neon is releasing electrons, not photons.

I agree that snapping a photo of light sounds dubious, but it looks like an electron flash, so maybe it's just making something visible that wouldn't have been seen otherwise.

Um... What?

[barfy]

Ok, Internet Physicists out there, please help me.

Ok, first you have this coherent photon beam. This means that they are all traveling at the same direction. So how do you take a picture of THAT?

You are bombarding the photon beam with photons, are the photons opaque, reflective, or TRANSPARENT? How do the photons from the flash, BOUNCE BACK at the camera. When they bounce back, how do you get color?

Is it just me, or does this make any sense at all?

Re:Um... What?

[TigerNut]

Richard Feynman once pondered, if moisture molecules in the atmosphere scatter light, and presumably this is a random effect because the molecules are randomly distributed, why is it that buildings, etc. when they're viewed through mist, do they still have sharp edges? You'd think all the random scatter would blur the edges.

That thought train led him to do some fundamental work in particle scattering and path integrals, IIRC, and eventually to the Feynman diagrams that are now commonly used to describe some aspects of particle interactions.

So you're thinking some good deep thoughts there, but I can't give you a good answer other than "they just know". Basically the "proper" reflection is the only one that is coherent to the observer and the other reflected beams are all out of phase so they might as well not happen... and therefore they don't. Or something like that.

Possible explanaition

[Anonymous Coward]

Here's a thought. You have a coherent photon beam. This doesn't just mean they are all traveling in the same direction, this also means that they are perfectly in phase with one another. Probably better to think about it as a single wave with a large amplitude. Anyways, you shine another pulse of light at it, the light passes through the laser beam, and hits a detector. Perhaps they are measuring the interference between the laser light and the light pulse or some such. Not exactly a reflective picture in the common sense, but a picture none the less..

Re:Who woulda thought?

[negRo_slim]

I prefer 'warticle' or a 'parve'. Fits in nicely with quark if I do say so myself.

Re:But...

[mikael]

Look at ocean waves travelling along the coast line. While a wave can be said to have energy through the momentum of water, there is no actual wave particle itself, just the interaction of all the water molecules interacting together, along with gravity to keep everything together.