Lasers Approach Their Ultimate Intensity Limit

Flash Modin writes "Death Star style superlasers? Don't bet on it. High-power lasers currently in development appear to be nearing the theoretical laser intensity limit, according to new research set to be published in the journal Physical Review Letters. Ultra-high-energy laser fields can actually convert their light into matter as shown in the late '90s at the Stanford Linear Accelerator (SLAC). This process creates an 'avalanche-like electromagnetic cascade' (also known as sparking the vacuum) capable of destroying a laser field. Physicists thought it might be a problem for lasers eventually, but this work indicates the technology is much closer to its limit than researchers believed. A preprint is available here."

Comments

Maybe, maybe not

[mcgrew]

Creating light from matter is rather ordinary in terms of physics, as can be seen in nuclear explosions

Or even running out of lighter fluid.

The SLAC experiment was just a singular event, but as lasers reach higher intensities the electric fields produced will increase as well and the team says that when they reach a critical intensity a cascade effect will occur as a result. The electron-positron pair is accelerated by the laser field itself at such high energies that they emit photons capable of spawning new pairs and continuing the process.

Maybe that's how the death star works? Besides, it isn't explicitly stated anywhere in the movies that the death star is a laser.

Also, they're not talking about a single laser, they're talking about colliding two laser beams.

Re:Maybe, maybe not

[erroneus]

Actually, from what I can see, the blaster, the death star's beam, the lightsaber and even the beam weapons on the clone wars gunship turrets seem to work on something other than "laser." They seem to operate on energized particles or energy that is transformed into a mass-like state. In the case of the death star, it would seem to explain why merging many beams from different angles could actually result in a single beam going in yet another angle.

In any case, you can see blaster bolts travel... they seem to fly at around arrow speed. The fact that they emit light leads people to think "laser" when in reality, you can't see a laser in most cases unless there is interference in the air. (BTW, did you ever notice that headlights seem to be less effective at night after a rainfall? That's because the roads are wet and more reflective... the light gets reflected away from your eyes and so you can't see the light bounce back to your eyes.)

Worse still, the term "laser sword" is actually used in Star Wars which doesn't help things at all. Young Anakin identifies Qui Gon as a Jedi because of his "laser sword." On one hand it is forgiveable because he's a kid, but on the other hand, he's a genius kid and should know better. In any case, lightsabers have a shadow (because of some sloppy film editing) but ostensibly because they are not lasers but an energy/matter transition state where energy is made to behave as matter. (Though only shown in games and cartoons, energy "bridges" are used to create temporary walkways using a technology similar to that used in lightsabers)

It's all fiction anyway, but it helps to try to understand the technology imagined in these fictions. The technologies imagined in SciFi are quite often candidate for implementation in our present or near future.

Re:Maybe, maybe not

[Fieryphoenix]

No, none of the matter was converted to energy. Chemical bonds were broken apart, and the energy that comprised them was dissipated as heat and light. Not one proton, neutron or electron was destroyed in the process.

Re:Maybe, maybe not

[John Meacham]

In truth, it does always bother me how easy it seems to 'blow up' planets in fiction. If you think about it, the amount of energy required to blow up a planet would be equivalant to launching every bit of the earth into space, think about the amount of energy involved in just getting the tiny space shuttle into space, then think about doing that for mount everest, then think about doing that for mount everest about 10,000,000,000,000,000,000 times. That is how hard it is to blow up a planet (very roughly)

http://qntm.org/destroy has some more good information on destroying the earth.