"HIGH-ENERGY laser weapons have been hailed as the future of anti-missile defence, but they may be further from being battle-ready than military chiefs hoped. In recent tests, several prototypes have suffered serious damage to their optics at intensities well below the expected levels of tolerance. "Optical damage has been quietly alarming upper management in most major programmes," Sean Ross of the US Air Force Research Laboratory in New Mexico told a meeting of the Directed Energy Professional Society in Newton, Massachusetts, last week. There are also big problems managing the waste heat generated by high-intensity beams. Laser weapons require mirrors and lenses to focus powerful beams onto distant moving targets, and to compensate for atmospheric perturbations that can reduce the power they deliver. The higher the intensity of the beam, the more likely it is to damage the surface of its optical components. Optical surfaces are designed to withstand powers up to a specific damage threshold, but tiny flaws or irregularities - which can be extremely difficult to spot - reduce this threshold by making them more vulnerable to heat. Contaminants deposited on the surface can also reduce this threshold by forcing the surface to absorb energy." - RAPatton from Bookmarklet

"Finding a way of preventing laser weapons from frying themselves is proving just as troublesome. Depending on the type of laser, generating 1 watt of laser 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." - RAPatton

Oops! - Scorpio