Military mega-l@sers are too hot to handle - tech - 10 July 2009 - New Scientist
“…. problems have begun to stall the development of laser weapons. Earlier this year in the US, engineers halted tests of the $4.3 billion megawatt-class Airborne L@ser short of full power to avoid damaging "a handful of optics in the turret", according to Mike Rinn, a Boeing vice-president who manages the programme. They realised that the optics, designed years ago, would be "frail" in the presence of any contamination, which would be virtually inevitable in flight. In the next week or so, Boeing engineers will install replacement optics and test them on the ground before running the laser at full power in flight.
Finding a way of preventing l@ser weapons from frying themselves is proving just as troublesome. Depending on the type of laser, generating 1 watt of l@ser beam produces about 4 watts of waste heat that must be dissipated. The challenge is to develop a cooling system that is both small and extremely robust.”