When you’re a gigantic skyscraper, you have to worry about getting hit by lightning. When the storm starts, people take shelter inside you, and you’re expected to just stand there stoically and take the hits. But now, researchers have an idea of how skyscrapers could defend themselves—they could use lasers to fend off lightning.
University of Arizona and University of Central Florida optical scientists say such beams of high-energy focused light can strip electrons from molecules in the air. This ionizes the molecules and leaves behind a plasma channel, which a lightning strike would see as a path of least resistance. This would attract the lightning and provide a route that it would follow down into the ground.
Now, one does not simply shoot a laser beam at a lightning bolt. There are still some big obstacles before this kind of system could work. First, any time you fire a high intensity laser beam into the atmosphere, it loses power in a few inches, as the water droplets suspended in air diffuse the beam. To fix that, researchers are experimenting with casing the high intensity beam in a low intensity beam that can extend much farther. The researchers detailed this process in a recent paper in Nature Photonics, and in that experiment they were able to take a beam that normally faded in just ten inches, and use the case to extend it to seven feet.
The lightning defense idea started with (shocker) a Department of Defense project that looked into way to shoot high-powered laser beams into the atmosphere for...a variety of reasons.