A new technology for application in underwater acoustics is using flashes of laser light to create underwater sound remotely.
Scientists at the Naval Research Laboratory have achieved the efficient conversion of light into sound by concentrating the light sufficiently to ionise a small amount of water, which absorbs laser energy and superheats, creating a small explosion of steam.
The slightly different colours of the laser, which travel at different speeds in the water, can be arranged so that the pulse also compresses in time as it travels.
As the driving laser pulse can travel through both air and water, a compact laser on either an underwater or airborne platform can be used for remote acoustic generation, which could improve undersea communications, navigation and acoustic imaging.
The news comes shortly after a team of researchers at the University of Illinois created the world's first acoustic superlens, which may further developments in ultrasound imaging and underwater stealth technology.