
Audio energy is used in sonar systems. The word "sonar" is another 
acronym, from "sound navigation and ranging." A sonar system has an active
transducer mounted on the ship's hull that, when driven by an electrical 
signal, will produce a loud, short ping. Programmed with the speed of 
sound in sea water, the sonar system can determine the distance of a 
target from your ship by sending out a "ping" and then measuring the 
azimuth and the returning echo. Using this information, an operator can 
locate the submerged object. In side-scan mode, the operator can "paint" 
the ocean bottom contour to verify the location of a vessel.
Light energy is used in laser systems. The word "laser" is another 
acronym, from "light amplified by stimulated emission of radiation." A 
laser is a unique form of coherent and focused light in the infrared or 
the blue end of the light spectrum. Laser systems are used for precise 
target ranging for guns or illumination for a missile seeker. The laser 
also may be used to illuminate targets for identification purposes. At 
present, no shipboard laser exists that is capable of being used as a 
weapon system. Perhaps in the future such a powerful system may be 
developed.

