Lasers could send messages right to a listener's ear

[Judi Lynn]

The new technique is the first of its kind that’s safe to use around humans
BY EMILY CONOVER 11:03AM, FEBRUARY 1, 2019

Lasers can send sounds straight to a listener’s ear, like whispering a secret from afar.

Using a laser tuned to interact with water vapor in the air, scientists created sounds in a localized spot that were loud enough to be picked up by human hearing if aimed near a listener’s ear. It’s the first time such a technique can be used safely around humans, scientists from MIT Lincoln Laboratory in Lexington, Mass., report in the Feb. 1 Optics Letters. At the wavelengths and intensities used, the laser won’t cause burns if it grazes eyes or skin.

The scientists tested out the setup on themselves in the laboratory, putting their ears near the beam to pick up the sound. “You move your head around, and there’s a couple-inch zone where you go ‘Oh, there it is!’… It’s pretty cool,” says physicist Charles Wynn. The researchers also used microphones to capture and analyze the sounds.

The work relies on a phenomenon called the photoacoustic effect, in which pulses of light are converted into sound when absorbed by a material, in this case, water vapor.

More:
https://www.sciencenews.org/article/lasers-could-send-messages-right-listener-ear?tgt=nr

[littlemissmartypants]

1. Very cool. nt