March 18, 2009--Northrop Grumman Corporation (Redondo Beach, CA) has produced the most powerful beam yet created by an electric laser, measured at 105.5 kW. The solid-state laser is made up of seven 15 kW plug-and-play units, each 38 in. x 28 in. x 12 in. in size, not counting the electrical power supply and the heat sink.
The company claimed ownership of this record by completing the final demonstration milestone of the U.S. military's Joint High Power Solid State Laser (JHPSSL) program, Phase 3. The achievements included turn-on time of less than one second and a continuous operating time of five minutes; the laser's electrical-to-optical efficiency was 19.3% and the beam quality better than 3.0. (Last year, Northrop Grumman's laser reached a JHPSSL Phase 3 power level of 15.3 kW in March, and a power level of 30 kW in September.)
"Our modular JHPSSL design makes it straightforward to scale laser-weapon systems to mission-required power levels for a variety of uses, to include force protection and precision strike missions for air-, sea- and land-based platforms," says Dan Wildt, vice president of Directed Energy Systems for Northrop Grumman's Aerospace Systems sector. He notes that the 100 kW threshold has been viewed traditionally as a proof of principle for "weapons-grade" power levels for high-energy lasers, but many militarily useful effects can be achieved by laser weapons of 25 kW or 50 kW, if they have good beam quality. "With this milestone, we have far exceeded those needs," Wildt adds.
Each building block for the laser consists of a laser amplifier chain, with each chain producing approximately 15 kW of power in a high-quality beam. Seven laser chains were combined to produce a single beam of 105.5 kW. The laser already has been operated at above 100 kW for a total duration of more than 85 minutes. A government team reviewed results of the demonstration during a System Test Data Review held Feb. 10 at Northrop Grumman's Directed Energy Production Facility in Redondo Beach.
The laser's seven beams are combined by "tiling" them in a row and matching their phases, thus coherently combining them, says Wildt.
The modular nature of the laser means that weapons could be created that emit as little as 15 kW (one laser chain) or as much as 120 kW (eight laser chains--a configuration not yet tested). Jay Marmo, Northrop Grumman's JHPSSL program manager, points out how the company's building-block approach also readily enables more-challenging missions that require well above 100 kW of laser power with a good beam quality. He notes that, combined with the company's Firestrike laser-ruggedization work, the ability to scale to these even higher powers shows the company's readiness "to bring high-power, solid-state lasers to the defense of our deployed forces." (The Firestrike laser is a ruggedized 15 kW laser unit that is fieldable; Northrop Grumman has announced that the Firestrike is ready for order.)
The technology could be deployed in as quickly as a year for a demo, says Wildt, and in a few years for a fieldable weapon system. The resulting laser weapons would be able to shoot down many types of enemy targets, including rockets, aircraft, unmanned aerial vehicles, missiles, mortar rounds, and swarming boats (an attack consisting of many small, explosives-laden boats that converge on a single ship).
--posted by John Wallace, johnw@pennwell.com
www.laserfocusworld.com
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