Researchers at the United States Naval Research Laboratory are developing laser acoustic technology that works underwater. It could make for better underseas acoustic imaging, and be used for remote communications between aircraft and underwater hardware and vessels because the signals can travel from the air into the water without degrading.
According to a press release from the Navy, the laser light–generated using a commercial laser–ionizes a small area of water, which superheats, creating an explosion of steam that generates pulses of sound waves at about 220 decibels.