Researchers at the U.S. Naval Research Laboratory (NRL) have conducted a long-distance acoustic-propagation and shock-generation demonstration of an underwater photo-ionization laser acoustic source.
This was the first successful demonstration performed by the physicist Ted Jones’ team at the Lake Glendora Test Facility of Naval Surface Warfare Center-Crane, Indiana.
The tests have extended the team’s previous laboratory research conducted on pulsed-laser propagation via the atmosphere. The pulses were projected by positioning mirrors down via a focusing lens as well as the water surface by using a Nd:YAG 532 nm laser enclosed in a floating platform. The laser pulse created an acoustic pulse with about 190 dB sound-pressure level that was determined and identified by hydrophones at maximum distances of 140 m, which is better than previous acoustic propagation distances of 3 m.
Jones stated that the objective of the laser acoustic-source development is to facilitate improved remote acoustic generation from small ship-borne and airborne lasers, eliminating the requirement for hardware source in the water. He added that the acoustic source could enhance and expand commercial and Naval underwater acoustic applications.