What to Know About the U.S. Lasers That Could Be Used to Counter Iranian Attacks

High-energy lasers are increasingly viewed as the most cost-effective way to defend against drones and missiles launched by Iran at oil refineries and U.S. bases across the Middle East. Shooting a laser is cheap — as little as $3.50 a shot, according to some estimates — compared with systems, like Patriot missile interceptors, that can cost more than $3 million per shot to neutralize a drone.

President Trump told reporters this week that lasers would soon be able to do the work of Patriot missile interceptors “at a lot less cost.”

“The laser technology that we have now is incredible,” he said. “It’s coming out pretty soon.”

The idea of using lasers this way isn’t new. American military leaders have spent decades trying to develop this technology, pursuing a dream of a weapon that can hit a target at the speed of light and never run out of ammunition.

Other countries, including Israel and China, have deployed high-powered lasers of their own. But the U.S. military faces significant challenges in its attempts to build and deploy them at scale. Experts in the industry said it could be years before American soldiers used lasers this way.

How do these lasers work?

High-energy lasers concentrate beams of light on a drone’s weak spots, frying its components like “a blowtorch at a distance,” said David Stoudt, executive director of the Directed Energy Professional Society, who helped invent a device to counter improvised explosive devices in Iraq.

Like a magnifying glass that is used to focus the sun’s rays to start a fire, lasers must lock on a drone for a period of time — three seconds or longer, under cloudy conditions — raising questions about their effectiveness in inclement weather or against a swarm of drones.