The U.S. Navy wants to put powerful lasers on its ships to shoot down artillery shells and even cruise missiles at the speed of light (and really, who wouldn't). But there are a few scientific details to sort out before sailors can deploy the beams. "First we want to make sure the physics is right before throwing buckets of salt water over the thing," says Ed Pogue.
Pogue is the program manager for Boeing's free electron laser (FEL) program, potentially the most ambitious laser weapons program since the Pentagon's controversial airborne laser. In that program, the Missile Defense Agency spent billions of dollars and over a decade to get a laser-rigged jumbo jet to destroy a ballistic missile in its boost phase of flight. They eventually succeeded in February 2010, but the Obama administration nixed plans to develop the experiment into a battle-ready weapon.
Maybe the Navy's project will meet a better fate. In 5 years, at a cost of $163 million, Boeing hopes to get the physics right and demonstrate an extremely powerful--and hopefully seaworthy--giant laser. It's no small task, in part because the laser they're using is powered by several particle accelerators.
Here's an overview of how the Navy's free electron laser works. (You may notice that the pictures are not on a boat; for now, researchers are working with a landlubbing laser based at Jefferson Lab in Newport News, Virginia.)