Good news, everyone! I expect we'll be discovering a lot of underwater wrecks, lost cities in the next few years.
"The Photoacoustic Airborne Sonar System, or PASS, fires a laser into the surface of the water, its intensity pulsed to the desired acoustic frequency, and as this laser energy is absorbed, it creates ultrasonic waves in the water that can act as effective sonar waves, bouncing off underwater objects before returning up to the surface.
“If we can use light in the air, where light travels well, and sound in the water, where sound travels well, we can get the best of both worlds,” said graduate student Aidan Fitzpatrick, first author on a study released through IEEE Access.
Moving back from the water into the air does sap these sound waves of nearly all their energy, but this one-way loss still leaves enough signal to be "heard" by transducers on the airborne device. “We have developed a system that is sensitive enough to compensate for a loss of this magnitude and still allow for signal detection and imaging,” said study leader Amin Arbabian.
Once the signal has been recorded, it's analyzed by software to create a 3D image of the submerged object. The software is able to correct for refraction of the sound waves as they come out of the water and into the air."
https://newatlas.com/marine/photoacoustic-airborne-sonar-system-stanford/
"The Photoacoustic Airborne Sonar System, or PASS, fires a laser into the surface of the water, its intensity pulsed to the desired acoustic frequency, and as this laser energy is absorbed, it creates ultrasonic waves in the water that can act as effective sonar waves, bouncing off underwater objects before returning up to the surface.
“If we can use light in the air, where light travels well, and sound in the water, where sound travels well, we can get the best of both worlds,” said graduate student Aidan Fitzpatrick, first author on a study released through IEEE Access.
Moving back from the water into the air does sap these sound waves of nearly all their energy, but this one-way loss still leaves enough signal to be "heard" by transducers on the airborne device. “We have developed a system that is sensitive enough to compensate for a loss of this magnitude and still allow for signal detection and imaging,” said study leader Amin Arbabian.
Once the signal has been recorded, it's analyzed by software to create a 3D image of the submerged object. The software is able to correct for refraction of the sound waves as they come out of the water and into the air."
https://newatlas.com/marine/photoacoustic-airborne-sonar-system-stanford/