Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 15/06/2010 17:43:35
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If you shone two lasers directly into each other, what would happen?
Asked by DavidWhalley94 via Twitter
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We put this question to Dr Graeme Hirst, from the STFC's Central Laser Facility...
Graeme - Well that’s a good question. If you shone them directly into one another, then you're quite likely to break the lasers unfortunately. But if you imagine you're going to misalign them slightly so that the beams crossed, but they don't go down the throat of the opposing laser, then if you were to do that in a vacuum, if you just have one light beam crossing another then to all intents and purposes, nothing happens. Once you get to extreme physics conditions where the laser intensity does become spectacular - and in some experiments we do, we’re getting there - you might imagine that you can perturb the vacuum. You can change the vacuum with the intensity of light you need. But mostly, this is interesting if you cross the two beams over in some kind of material, and if you do that, you can achieve all sorts of interesting effects in the material by combining two laser beams, through the properties of the material.
Go to the show page for more. (http://www.thenakedscientists.com/HTML/podcasts/show/2010.06.13/)
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From the laser's point of view you get the same effect as you would get by placing a mirror in front of the laser.
Unless you have a very high powered laser the effect is nothing much. More light is dissipated out of the sides of the laser. I have, incidentally, done this with several lasers and can vouch that you are not, in my experience, likely to break the lasers.