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Scientists have devised a way to communicate in secret by sending laser-transmitted messages directly to the ear.
Humans love to talk to each other and often do so in ways that prevent them from listening. This new research could have potential military applications – but will you know where else might be useful?
"The ability to communicate with a specific subject in a specific place, devoid of any communication equipment, opens many intriguing possibilities," according to the authors. written in the article recently published in Optics Letters .
How would such a device work? It can be helpful to understand what is actually sound: pulses or vibrations that pbad through air molecules to our eardrums, which then vibrate, thus becoming the badog input that our brain interprets as a specific sound. 19659003] The device generates sounds in the air with the help of a process called photoacoustic effect. Researchers give laser light at a specific wavelength which, they know, will make the water molecules vibrate in the air, but it will not cause any damage to the eyes.
However, the laser only causes molecules. vibrate – the researchers had to introduce another element to give the water molecules ambient air more sound than just a drone or impulse. Previous experiments, like this one, used an instrument called an "acoustic-optical modulator" to alter the strength of the laser pulse and, in turn, the behavior of the water molecules. But as part of this work, researchers have also developed a new method in which the laser first goes into a fast-rotating mirror, which essentially expands the laser beam. The size adjustment of spreading produces different frequencies.
The new method produced higher sounds than an older method, according to the article; the sounds were boosted to 60 decibels, roughly the volume of background music. I asked the authors of the study to describe listening to these specially created sounds.
"Perhaps the most fun was listening to the dynamic photoacoustic system. We had to position our ears in the right place (a few inches long) to hear the sound, otherwise we would not hear anything It was a somewhat strange but satisfying effect "said Charles Wynn, head of the research team and a member of the Lincoln Laboratory at MIT.
Wynn also talked about the messages that were transmitted, describing that they were the first unique tones and frequency sweeps using traditional and dynamic photoacoustic communication techniques
"We then released some forms of 39; more advanced wave such as lyrics and music (including Miley Cyrus "Malibu") using the traditional photoacoustic setting.With a little more engineering, we hope to be able to design a dynamic photoacoustic communication system with the bandwidth needed to encode and transmit the most detailed audio messages. "
This work was only a proof-of-concept study; the sound could only be transmitted to the receivers at a short distance – 2.5 meters – according to the article. But researchers are working to extend their method of work to greater distances.
There are many strange scenarios in which you can imagine the need to send a secret message by means of laser pulses. In my dreams, they will replace the digital stations that give me nightmares.
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