New laser acoustic propagation experiments, performed at the Lake Glendora Test Facility of Naval Surface Warfare Center-Crane, expanded and improved on initial 2010 tests. A Plasma Physics Division research team led by Dr. Ted Jones made the first intermediate distance acoustic directivity measurements of their novel underwater photoionization laser acoustic source in June 2011. In addition, their preliminary analysis indicates that the acoustic detection distance doubled in the new tests to 280 meters, thereby expanding the potential applications of this Navy acoustic source.

Housed in a floating structure, the Nd:YAG laser (bottom left) generates underwater acoustic pulses, which travel to a distant hydrophone-equipped boat (bottom right).
Housed in a floating structure, the Nd:YAG laser (bottom left) generates underwater acoustic pulses, which travel to a distant hydrophone-equipped boat (bottom right).

Background: Together, the 2010 and 2011 field experiments culminate a 6.2 Base Program to develop laser acoustic generation, demonstrate acoustic source control, and optimize laser acoustic transmission in open water.

Accomplishment: Laser acoustic transmission distance was doubled over previous field tests, and important far-field acoustic directivity characterization measurements were made.

Significance: Improved acoustic transmission range and directivity characterization significantly expands the utility of this technology for potential Navy applications such as acoustic communications and sonar.

Application: Potential Navy applications of this acoustic source include communication with underwater vessels and equipment, rapid sonar search and detection of underwater mines and vessels, mapping underwater terrain, and navigation using remotely generated laser acoustic beacons.