The U.S. Navy’s most advanced laser weapon looks like a pricey amateur telescope, and, at just 30 kilowatts, it’s hardly the megawatt monster military scientists dreamed of decades ago to shoot down ICBMs, but it is a major milestone, built on a new technology:
The mission shift has been going on for years, from global defense against nuclear-armed “rogue states” to local defense against insurgents. The technology shift has been more abrupt, toward the hot new solid-state technology of optical-fiber lasers. These are the basis of a fast-growing US $2 billion industry that has reengineered the raw materials of global telecommunications to cut and weld metals, and it is now being scaled to even higher power with devastating effect.
Industrial fiber lasers can be made very powerful. IPG recently sold a 100-fiber laser to the NADEX Laser R&D Center in Japan that can weld metal parts up to 30 centimeters thick. But that high of a power output comes at the sacrifice of the ability to focus the beam over a distance. Cutting and welding tools need to operate only centimeters from their targets, after all. The highest power from single fiber lasers with beams good enough to focus onto objects hundreds of meters or more away is much less — 10 kW. Still, that’s adequate for stationary targets like unexploded ordnance left on a battlefield, because you can keep the laser trained on the explosive long enough to detonate it.
Of course, 10 kW won’t stop a speeding boat before it can deliver a bomb. The Navy laser demonstration on the USS Ponce was actually half a dozen IPG industrial fiber lasers, each rated at 5.5 kW, shot through the same telescope to form a 30-kW beam. But simply feeding the light from even more industrial fiber lasers into a bigger telescope would not produce a 100-kW beam that would retain the tight focus needed to destroy or disable fast-moving, far-off targets. The Pentagon needed a single 100-kW-class system for that. The laser would track the target’s motion, dwelling on a vulnerable spot, such as its engine or explosive payload, until the beam destroyed it.
Alas, that’s not going to happen with the existing approach. “If I could build a 100-kW laser with a single fiber, it would be great, but I can’t,” says Lockheed’s Afzal. “The scaling of a single-fiber laser to high power falls apart.” Delivering that much firepower requires new technology, he adds. The leading candidate is a way to combine the beams from many separate fiber lasers in a more controlled way than by simply firing them all through the same telescope.
There’s much, much more.
The leading candidate is a way to combine the beams from many separate fiber lasers in a more controlled way than by simply firing them all through the same telescope.
So something like this?
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