Andy Motes, Directed Energy Manager, was recently featured in LaserFocusWorld discussing how we’re ruggedizing high-energy lasers for the battlefield. Highlights pertaining to Schafer’s contribution to the article are below; you can view the entire article at Laser Focus World.
Rugged Battlefield Lasers
Solid-state lasers have reached the 100 kW class, and demonstrated that they can shoot down militarily important targets. The next challenge is to harden laser systems enough to withstand the rigors of operating in warplanes, on battleships, and on the battlefield.
Optical damage and measurement
“Optical damage is a huge issue,” says Andy Motes, directed-energy manager at Schafer Corp.’s military aerospace office (Albuquerque, NM). Dust and dirt in the military environment magnifies risk of damage inherent with high-energy beams. Damage mechanisms include surface contamination, internal contamination of dielectric coatings, and dielectric breakdown at very high intensity. If the laser beam ignites a bit of fuzz, he says that “the carbon deposits settle and can absorb light, heating and destroying the optics.” Humidity can cause delamination of optical coatings, leading to damage. Working in vacuum can avoid contamination unless vibrations break the seal. He likes fiber lasers: they reduce exposed surfaces, but says “even if you use fiber lasers, you have some free-space optics.”
Improving efficiency can ease cooling requirements. “Everybody’s fighting to get efficiency,” says Motes. “At least initially we will need a low-duty cycle on the order of 10% to deal with cooling and power requirements.” However, efficiency is increasing, and he hopes to reach overall electrical-to-optical efficiency of 40% in five to 10 years, easing cooling needs.
The big challenge is to take these high-energy lasers to the next level, ready to operate under harsh military conditions that pose problems different from those on the factory floor. That will take time, money, and energy. While there is no guarantee it’s possible, we’ve already come an amazing distance.