Photoacoustic communication approach could send warning messages through the air without requiring a receiving device
Researchers have demonstrated that a laser can transmit an audible message to a person without any type of receiver equipment. The ability to send highly targeted audio signals over the air could be used to communicate across noisy rooms or warn individuals of a dangerous situation such as an active shooter.
In The Optical Society (OSA) journal Optics Letters, researchers from the Massachusetts Institute of Technology’s Lincoln Laboratory report using two different laser-based methods to transmit various tones, music and recorded speech at a conversational volume.
“Our system can be used from some distance away to beam information directly to someone’s ear,” said research team leader Charles M. Wynn. “It is the first system that uses lasers that are fully safe for the eyes and skin to localize an audible signal to a particular person in any setting.”
Creating sound from air
The new approaches are based on the photoacoustic effect, which occurs when a material forms sound waves after absorbing light. In this case, the researchers used water vapor in the air to absorb light and create sound.
“This can work even in relatively dry conditions because there is almost always a little water in the air, especially around people,” said Wynn. “We found that we don’t need a lot of water if we use a laser wavelength that is very strongly absorbed by water. This was key because the stronger absorption leads to more sound.”
One of the new sound transmission methods grew from a technique called dynamic photoacoustic spectroscopy (DPAS), which the researchers previously developed for chemical detection. In the earlier work, they discovered that scanning, or sweeping, a laser beam at the speed of sound could improve chemical detection.
“The speed of sound is a very special speed at which to work,” said Ryan M. Sullenberger, first author of the paper. “In this new paper, we show that sweeping a laser beam at the speed of sound at a wavelength absorbed by water can be used as an efficient way to create sound.”
For the DPAS-related approach, the researchers change the length of the laser sweeps to encode different frequencies, or audible pitches, in the light. One unique aspect of this laser sweeping technique is that the signal can only be heard at a certain distance from the transmitter. This means that a message could be sent to an individual, rather than everyone who crosses the beam of light. It also opens the possibility of targeting a message to multiple individuals.
In the lab, the researchers showed that commercially available equipment could transmit sound to a person more than 2.5 meters away at 60 decibels using the laser sweeping technique. They believe that the system could be easily scaled up to longer distances. They also tested a traditional photoacoustic method that doesn’t require sweeping the laser and encodes the audio message by modulating the power of the laser beam.
“There are tradeoffs between the two techniques,” said Sullenberger. “The traditional photoacoustics method provides sound with higher fidelity, whereas the laser sweeping provides sound with louder audio.”
Next, the researchers plan to demonstrate the methods outdoors at longer ranges. “We hope that this will eventually become a commercial technology,” said Sullenberger. “There are a lot of exciting possibilities, and we want to develop the communication technology in ways that are useful.”
The Latest on: Photoacoustic communication
via Google News
The Latest on: Photoacoustic communication
- News tagged with communication channelon June 18, 2020 at 5:00 pm
Photoacoustic imaging ... A new study shows that communication channels between different parts and pieces of computer software are prone to security breaches. Anyone with access to a shared ...
- DARPA PIPES Program demonstrates 2 Tbit/s optical interconnects at the chip levelon June 16, 2020 at 7:46 am
Data communication propagates over optical fiber systems and networks until hitting a bottleneck at copper interconnects, the fundamental point-to-point conductive components on microchips and circuit ...
- APS Fellowshipon June 14, 2020 at 5:00 pm
Citation: For significant scientific advancement in the application of plasma-based electronic systems to advanced space communications, and for the advancement of systems and processes necessary to ...
- Video Explains Photoacoustic Gas Monitoringon June 4, 2020 at 5:00 pm
Jun 5th, 2012 Offering a low maintenance, cost-saving solution in situations where vapor interference or contaminants preclude the use of other measurement techniques, the reliable PA4000 ...
- Thomas Jefferson University-led group creates first 3D map of heart neuronson June 2, 2020 at 3:39 pm
The normal functioning of the human heart is maintained by the the brain via an intricate network of nerves. When this communication is disrupted, it can result in heart disease, including heart ...
- Explosive Growth of Photoacoustic Imaging Market | Competitive Outlook By Kibero, Medtronic, LivaNova, BIOTRONIK, Canon, Hitachi, PreXionon May 20, 2020 at 8:16 am
Press release from: Data Bridge Market Research Pvt. Ltd. Global Photoacoustic Imaging Market - Industry Trends and Forecast to 2027 The Photoacoustic Imaging market report shares exhaustive ...
- Correlated unpolarized photons enable camouflaged secure communicationon May 18, 2020 at 5:00 pm
Exploiting the infinite number of polarization states of unpolarized thermal light and their correlation properties leads to a new approach for secure data communications. The researchers developed an ...
- Photoacoustic Imaging: Peering Inside the Body using Lasers and Ultrasoundon February 26, 2020 at 11:13 am
Caltech’s Lihong Wang, a pioneer in medical imaging, has developed a new type of photoacoustic imaging ... are sent in a single stream through one communication channel. In parallel transmission ...
- Selected Achievements: Tumor Microenvironment & Metastasison June 15, 2019 at 4:13 am
Nature communications 101, 279 (2019/Jan 17 ... Verkhusha, V.V., and Wang, L.V. Multiscale photoacoustic tomography using reversibly switchable bacterial phytochrome as a near-infrared photochromic ...
- Scientists Figured Out How to Send Secret Messages to Your Ear With Laserson January 27, 2019 at 5:05 am
“The ability to communicate with a specific subject at a prescribed location who lacks any communication equipment ... the air using a process called the photoacoustic effect.
via Bing News