What’s the best way to communicate with a person when they’re outside of normal speaking distance? Call them on their phone, obviously. But what if the person either doesn’t have a phone with them — or you’re just looking for a high-tech communication method that’s a little more James Bond in its nature? Researchers from Massachusetts Institute of Technology have you covered with a new invention that makes it possible to literally beam an audible message to a specific person across the room using a laser. Because, you know, science.
“We have demonstrated that an eye-safe laser will heat the water molecules in the air, via the well-known photoacoustic effect, to create a local sound,” Ryan Sullenberger, a researcher who worked on the project, told Digital Trends. “We have also leveraged the special behaviors that occur at the speed of sound to help us amplify and localize the sound. If we rotate our laser beam, we can localize the sound not only along the laser path, but also isolate a specific range — the one at which the beam is moving at the speed of sound — at which the signal is amplified to an audible level.”
As noted, in most cases, calling someone’s phone is a whole lot easier than communicating with them via laser. That’s particularly true due to the fact that, unless both people possessed the same equipment, this is a one-way communication process only. However, Sullenberger noted that there are specific situations in which this could prove to be useful, rather than simply a cool proof-of-concept tech demo. For example, it could be used for gaining the attention of individuals in potentially dangerous situations when they are out of ordinary earshot.
At present, the technique can be used to send sounds up to 60 decibels (equivalent to ordinary background music or a conversation in a restaurant or office) a distance of around 2.5 meters. But this distance could change in the future. “We are [next] hoping to make measurements at longer ranges [of around] 100 to 500 meters, outside, to better understand issues that might occur outside of a controlled laboratory setting,” Sullenberger said. “We are currently working on patenting the technology and would love to engage with interested parties.”
A paper describing the research was recently published in the journal Optics Letters.