Greedo and I were in the Cantina the other day, talking about this very topic…
Not unless you’re really, really close to your target (in which case, you’d be better off using a knife). Thermal bloom happens inside the target, not inside the gun, and the effects will reach you only by travelling through the air, so they’ll fall off and dissipate very quickly with distance.
Don’t forget that the laser has to burn a hole through the air. I’ve been told that high powered lasers make a great deal of noise when fired.
I’m puzzled as to why this should be necessary. If the air contains particles, these could absorb photons - but the air itself should do very little of this.
Air is particles, if you stop and think about it.
Blasters develop out of Tractor Beam Tech.
Imagine a Tractor Beam, forcused on a 1 Square Centimeter area, with a 2 kilogram pull.
Then, reverse this to a 2kg push.
Repeat, 5,000 times a second.
The target will blast apart quite nicely.
I was thinking of the air that is superheated around the muzzle as the laser beam exits the barrel.
Edit: I should’ve read some more: kind of what Tuckerfan is saying.
Right - molecules. But unless there are some larger particles hanging around, its ability to absorb photons is distinctly limited. I can see no real reason why a laser should have to “burn a hole through the air.”
Thermal blooming is a very real problem for high power (>100kW) lasers. The abstract of this paper gives a basic explanation of the phenomenon:*The distortion of the laser beam is the result of heating of the path by absorption of a small fraction of the laser beam power by the medium which changes the index of refraction and therefore distorts the beam. Thermal blooming effects can limit the laser powers which can be effectively propagated through the atmosphere, or in media which absorb laser power such as industrial or laboratory environments, liuquid or gas cells, or even laser active media themselves.*In short, a small fraction of the energy is absorbed by the volume of atmosphere it travels through, the heating caues this mass of air to become turbulent, which increases its refractiveness and amplifies absorption, ad nausum. This is a significant problem with high energy lasers, particularly those in optical or near-optical spectra, and for all the talk about adaptive optics it remains a stumbling block in strategic laser defense applications.
But none of this is going to cause a laser weapon to recoil. Recoil in firearms is due to conservation of momentum from a reaction to the impulse imparted in ejecting a bullet and gases exit out the barrel. The amount of impulse in even a high power laser is insignficant compared to the mass of the lasing cavity and media, not to mention anything small enough to be wielded by hand.
Recoil has virtually no direct effect upon the accuracy of a weapon, since the largest impulse comes immediately after the bullet leaves the barrel. However, particularly with handguns, flincing in anticipation of recoil is a major cause of inaccuracy, and of course higher recoil limits how fast a shooter can accurately aim and fire a second shot. There would be no conceivable benefit to simulating recoil on a hypothetical pistol-sized laser.
Stranger
Stranger’s right (as always)… Look on wikipedia for the Kerr effect, or optical Kerr effect. Basically, all materials will have a change in thier index of refraction proportional to the intensity in the beam. For a gaussian beam, this produces what is in effect a grin lens which focusses the beam until catastrophic failure occurs. Even in air. I worked (briefly) in an ultrafast laser lab and played around with chirped pulse amplification to get ultra high peak power laser pulses. Amazingly, wikipedia has an entry on CPA too…
I’ll concede the point about thermal blooming while continuing to believe that it’s a bit misleading to describle this as burning a hole through the air.
According to the laser trooper cheat in Age of Empires, lasers make a kinda crackling noise. Don’t know about recoil, though.
When the light intensity is high enough, the E field intensity is sufficient to ionize the air. Given that a flame is ionized gas, it is not a discription that falls very far from reality. This happens with lasers of less than ten watts if the beam is focused to a point, and is one of the limiting factor when attempting to drive single mode fibre.
I had neglected the atmospheric effects, on the notion that air should be almost completely transparent to a laser beam. But I suppose that, for a weapon-power laser, that probably would be a consideration.
Then again, it sounds like, before the bloom would get to a point where it would cause a detectable recoil, it would make it ineffective against the target, as well. So any practical laser weapon which is eventually developed would have to have some workaround to this problem (don’t ask me what it would be). So maybe it is justified to neglect it?