the idea of laser weaponry's pretty cool but no one seems to point out the obvious if a lasers just light, wouldn't all you need to defend your missiles/planes etc be just a mirror? or some other light scattering device a prism maybe? Laser fires at missile and cuts a hole in a passing soldier?

its a frikken death ray "laser", post me one along with my flying car

I'm sure with a little software update they'll be excellent for burning out the eyes of the enemy too.

"if a lasers(sic) just light" - no, a laser is just e.m. radiation - and the common or garden type happens to be in the visible spectrum.

Not sure what part of the spectrum these are supposed to be in but you can be they're not in the vis spectrum..

So the laser protects the troops from the bombs who's gonna protect the troops from the laser? especially when all that nice dangerous toxic fuels released by "friendly fire"

> Not sure what part of the spectrum these are supposed to be in but you can be they're not in the vis spectrum..

Well, infrared is well reflected by shiny metal coatings, too.

And there are no ultraviolet or X-ray lasers outside of the lab building housing the synchrotron.

It's all about the heat. If you stick a mirrored surface in front of a laser it will still get hot, which is the reason for using a laser. Sure some of it will be mitigated, but this will also now make them more vulnerable & traceable to other currently in use weaponry.

That will just about cover the cost of writing the functional spec. Which means we're safe for a good bit yet.

I think they'd do better with a humongous magnifying glasses slung underneath a Chinook chopper, and a targetting system written in Forth.

"if a lasers just light, wouldn't all you need to defend your missiles/planes etc be just a mirror? or some other light scattering device a prism maybe?"

The problem is that mirror's only reflect a percentage of the light that hits them, some of it is still absorbed. That bit that is absorbed heats it up and eventually the mirror gets vapourised (by eventually we're talking fractions of a second at the power levels that would be needed to destroy the incoming object behind the mirror).

I'm not entirely sure with lasers, but as I understand it, they belt out light at a single frequency. Prism's split light into different frequencies so it would only change the laser beams direction, rather than split it in different directions (and thus dissipate its power). I think however that the prism would also suffer the same problem as the mirror and be destroyed in fractions of a second.

Still, there are several other problems that need to be overcome yet, such as generating the power levels required to destroy a shell, or being able to fire at a shell and not having to wait 10 minutes or so for the laser to recharge.

Anyone of these armchair laser designers been on a real battlefield? Anyone thought of dust, smoke etc?

If you try fire a laser through smoke or dust all that yummy energy will get soaked up in the air between the firer and the firee.

This will have two effects:

(1) leave the target pretty much unscathed.

(2) make defensive armour very simple. Just head down to the local bazaar and stock up on incense sticks.

A solid state laser's efficiency is not that great: 18 - 25% is sometimes quoted as good. This means that the rest of the energy (75-82%) must be dissipated by the weapon system itself, whereas a good mirror can reflect up to 99% of the 18-25% of the ennergy. A more conservative 95% is more realistic, meaning that the target (including mirror shield) recieve roughly 1% of the total energy, i.e. 75-82 times LESS than the weapon itself must get rid of somehow. Unless the energy efficiency of lasers is boosted a great deal, I do not think it will be very practical.

It may of course be difficult to coat artillery shells with a shiny coating which survives being fired out of a gun (though for so-called sabot shells it may be quite easy), but for missiles it is probably easier.

Dust, smoke and water vapour are indeed also problems, though (in particular the for the first two) less to infrared light than in the visible spectrum. Insurgents firing RPG's during a sand-storm will not see their rockets zapped.

BTW: B.o.t.E. = Back of the Envelope (i.e. G.E.f.G.W (good enough for goverment work))

How do you lay a smokescreen if you are in a plane? The smoke will end up behind you.

Maybe you could use smokebombs or smoke rockets or something? Ahh, exactly the sort of things that this weapon would be designed to counter.

And as for mirroring, perhaps you should think for a little bit about how you'd make a smooth, spotless mirrored surface over the whole of a aircraft. Including the engine exhausts. I don't imagine for one moment that this would be easy to do with an artillery round or mortar bomb either, given the stresses inflicted on them by firing, and that's even before we start worrying about making some kind of ultra reflective, super insulating laser armour which is yet still compact and lightweight.

Sure, lasers won't be terribly useful against ground vehicles (easier to armour, smokescreens etc), but if you read the article that was never the intention of the system anyway.

And whilst i'm ranting, you won't find x-ray lasers out of the lab (though people have though about it... see the good old SDI) but UV lasers do exist, in the near ultraviolet range at least.

If air superiority go bye-bye, how long til we're all piloting vertical tanks or big stompy robots?

Hmmm. Big and stompy. Yes ! Bring on the Mechwarriors !

It's a new way of getting hot-off-the-stove supplies to allied forces - Hugh Fernley Whittingstal (sic?) fires a raw ICBM (Inter Continental Bag of Munchies) from his cottage bunker, as it approaches the target base, the laser blasts it, cooking it's contents, showering the hungry soldiers in lovely cooked pieces of lamb and bacon.

http://uk.youtube.com/watch?v=NfVJ622_hS0

Robin

Or would these applications also work on MASERs? I believe those can use more power, and mirrors, dust, etc. shouldn't do too much to block a coherent microwave beam.

I saw these years ago the japanese had a bunch of them

to fight Godzilla with they didn't work that well IIRC.