Lasers could beam messages directly to a listener’s ear ‘like whispering secret from afar’, scientists say
SOUND IDEA Lasers could beam messages directly to a listener’s ear ‘like whispering secret from afar’, scientists say
It's hoped the technology could one day be used for headphone-free TV watching without disturbing others or warning people of danger discreetly in situations like an active shooter attack
By Nika Shakhnazarova 2nd February 2019, 1:39 am
LASERS could be able to beam messages directly to a listener's ear, like "whispering a secret from afar", according to scientists in the US.
The laser interacts with water vapour in the air, as scientists created sounds in a localised spot that were loud enough to be picked up by human hearing if aimed near a listener’s ear.
This is the first time this technique has been used safely around humans, scientists say.
It's hoped the directed sounds could one day be used for headphone-free TV watching without disturbing others.
Or they could warn people of danger discreetly in situations like an active shooter attack.
The laser will not cause burns to eyes or skin due to scientists finding the exact wavelength level that allows it to be risk-free.
Researchers tested out the setup on themselves in a laboratory, putting their ears near the beam to pick up the sound, reported Science News.
Physicist Charles Wynn said: “You move your head around, and there’s a couple-inch zone where you go ‘Oh, there it is!’… It’s pretty cool.”
Microphones were also used to capture the sounds that were being produced.
WHISPERING FROM AFAR
The photoacoustic effect, in which pulses of light are converted into sound when absorbed by a material, allows the unprecedented phenomenon to take place.
Researchers tested out two different techniques in order to achieve the sounds.
The first technique involves rapidly ramping the intensity of the laser beam up and down, which transmitted voices and songs.
Physicist Ryan Sullenberger said: “You can hear the music really well; you can understand what people are saying.”
The second method involved using a rotating mirror while researchers swept the laser beam in an arc.
The noise was heard only at the distance along the beam where the light passed by at the speed of sound.
The noise sounds like a buzzing insect, as so far it unable to send complex messages.
Researchers aim to improve this targeted method to send detailed audio messages as well as increase the distance over which it works.
But physicist Jacob Khurgin admitted: "It’s not as much a practical means of communication, but a very neat demonstration proving the power of photoacoustics."