

Despite Your Skepticism, Lasers Are Being Used By The Military - mielles
http://www.futureofgadgets.com/futureblogger/show/1338-despite-your-skepticism-lasers-are-being-used-by-the-military

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mechanical_fish
Installed on a single Humvee does not equal "being used". Lasers are being
_demoed_ by the military, just as they have been for years, and just as they
will be for as long as the R&D money holds out.

 _There’s no ammunition concerns, just power, and despite being totally un-
serviceable in the field, the lack of moving parts makes the possibility of
breaking very slim._

This is so hilarious it makes my sides hurt.

First, there's the phrase "just power". As if you could run a military laser
on a pair of AA batteries. As if the _N_ kilowatt portable generator, the
gigantic battery pack, the capacitor bank, and/or the long extension cord
trailing behind you aren't pretty big handicaps to your movement and your
logistics, just as ammunition is.

"Lack of moving parts?" Sounds like someone doesn't understand lasers. For one
thing, although lasers are the most efficient converters of electricity to
light in the world, their wall plug efficiency is still only of order 50%.
That means that for every joule you pump into the enemy, you're generating a
joule of waste heat. This works, because the heat is more concentrated at the
far end than it is at your end. But you still need a high-performance cooling
system. And your cooling system contains... moving parts! Coolant! Pumps! Heat
exchangers! All of which can break down, and which tend to weigh a lot.

The other problem is that you only _think_ the laser has no moving parts. But
I assure you that deep inside the sealed packages, deep inside the crystals
where the action is, atoms are moving. Metals are migrating. Defects are
migrating. Meanwhile, on the outside, dust motes are fusing themselves to your
lenses. So there's only so many shots you're going to get out of your laser
before it dies _forever_ and needs to be replaced. Particularly if you're
running it at high power, which keeps it under a high temperature.

