Researchers at MIT have discovered a way to send audio signals directly to someone's ear at a distance using laser beams. The system uses a photoacoustic effect in which water vapor in the air absorbs light then forms sound waves.
This research could pave the way for allowing audible messages to be sent to agents, spies or possibly law enforcement, warning them of encroaching danger.
Researchers used a laser beam that fired at wavelengths absorbed by water. By sweeping the beam at the speed of sound, they were able to generate sound that can only be heard at distance from the transmitter.
After many tests, they discovered this would allow a message to be sent to a specific individual instead of just anyone who happened to be passing by the laser path.
The scientists said this system can be used in dry locations because, at any given time, there is moisture in the air, especially around people. Also, the lasers are very safe to one's ears, eyes, and skin while localizing an audible signal to an individual at any setting.
They also discovered a method that works by modulating rather than sweeping a beam. The traditional modulation method offers sound with a much higher fidelity where the laser sweeping offers a sound with louder audio.
To date, the system will work at more than 8 feet or 2.5 meters. Scientists are currently working to increase the distance and believe they will eventually have a very significant commercial technology for future use.
We look forward to hearing more about this new and exciting technology, so stay tuned!