Flying lasers don’t have the best track record. An Air Force program to burn intercontinental ballistic missiles out of the sky from a 747 crashed and burned. But the Navy’s aviators think sensors might be a more realistic target to fry from the sky.
Last November, the Naval Aviation Systems Command in New Jersey solicited bids to build lasers mounted on planes that could destroy optical sensors below. By next week, the Navy should be ready to move to a prototyping stage. And in a few years, adversaries tracking the movement of U.S. planes, ships and troops could find their sensors a smoldering mass of melted parts.
“If you’re in some sort of aircraft that’s overlooking territory beneath, you could keep the laser system constantly on, aiming it at the ground and tuning its wavelengths, hoping to destroy whatever sensors are there,” says Brandon Conover, an engineer with Bennett Aerospace, one of the companies given $80,000 in initial seed money to develop the laser.
Except Conover’s idea isn’t to invent a new laser. It’s to affix an oscillator to an existing one, much as you’d attach a silencer to the barrel of a gun. A laser beam passing through the oscillator would run through a maze of mirrors and “non-linear crystals,” Conover explains, distinct from the mirrors that helped generate the initial beam — until it passes out the other end at a different wavelength than it started.
That way, the Navy can switch up the wavelengths of a laser to kill many, many different optical sensors, which track motion or the presence of an object. Some sensors come with protective shields or coatings to make certain light wavelengths impenetrable, similar to how your sunglasses are good at reflecting ultraviolet radiation. A single laser beam won’t be able to get every sensor. But.
“If we have a sensor that’s immune to two specific wavelengths, but not the wavelengths between those two, then we can destroy that sensor by adjusting the wavelengths,” Conover explains.
Adjust the knobs on the oscillator, and you change the configuration of the internal crystals, generating different laser wavelengths. The whole device, designed by Bennett’s partner company AS Photonics, is about the size of a Kleenex box — no need for a giant 747 to hoist it, like with the Airborne Laser. Known as the RISTRA, it looks like this:
Also, savor the irony: since 1998, an international ban on blinding laser weapons has held force, in order to preserve everyone’s eyes. Build an electronic eye, however, and you open yourself up to no-holds-barred laser action.
Still, this isn’t the happiest time for the Navy’s laser programs. On Friday, a key Senate panel recommended terminating the service’s premier experimental laser, the Free Electron Laser. Ironically, that’s another laser capable of generating beams at multiple wavelengths.
But the potential cancellation of the Free Electron Laser doesn’t impact Conover’s efforts. He’s just waiting to hear if the Navy will select his design to move on to the second stage of testing, in which he’ll have to deliver a prototype. Word should come by next week. By 2015, the entire laser project should be ready to give the Navy a tool to cook sensors.
Nor is he concerned about his design falling victim to the same flaws that plagued the Air Force’s beloved flying lightsaber. ”The Airborne Laser didn’t focus on tunable wavelengths, and you had to put a ton of power into it,” Conover says. “If you address a more specific wavelength, then you can be more efficient, and you don’t have to put gobs and gobs of power in to be effective.” Sensors, look out below.
Posts
