WHY THIS MATTERS IN BRIEF

Being able to use lasers to create sound opens up a weird array of new use cases, from crowd control to just plain being able to freak people out…

Within three years, the US Pentagon’s non-lethal weapons lab hopes to have a direct energy weapon that can produce an effect like a haunted walkie-talkie or the biblical burning bush, and they’re using the same technology that was recently used to create some interesting interactive holograms to do it.

Watch the video below and listen carefully for what sounds like a human voice, albeit a very creepy one, during the second spin. That’s not an audio recording or a broadcast transmitted over radio…it’s not human at all. It’s an auditory effect that’s created by military scientists who manipulated the air with lasers — and it’s the Pentagon’s most interesting idea for stopping people charging checkpoints, or just scaring the crap out of them.

The US military’s Joint Non-Lethal Weapons Program, or JNLWD, is inching closer to a weapon that alters atoms to literally create words from thin air. It’s called the Laser-Induced Plasma Effect and, fingers crossed, they hope to be able to say intelligible words within the next three years.

Lasers that talk… weird but now a thing?

The weapon is composed of two parts: first, a femtosecond laser, which shoots a burst of focused light for 10−15 seconds, just long enough to rip the electrons from air molecules and create a ball of plasma. Sometimes called the fourth state of matter, plasma is a field of electrified gas, highly responsive to electromagnetic effects. The scientists then hit that plasma field with a second nanolaser, tuned to an extremely narrow range of wavelengths. They use that to manipulate the plasma field in a way that can produce light and noise. Get the interaction precise enough and you get something that sounds like a haunted walkie-talkie.

“We’re this close to getting it to speak to us. I need three or four more kilohertz,” says David Law, who runs JNLWD’s technology division. Ultimately, he wants a single system that can produce multiple effects — noise, light, even heat — and replace a wide variety of non-lethal weapons that the military has been testing.