Laser deflector shields around ships or airborne platforms seem like the stuff of Star Wars, but the science behind them is not only plausible, but possible. In fact, plasma generated by lasers has many more benefits to the warfighter than just this futuristic defense mechanism.
At the Space and Naval Warfare Systems Center Pacific, research into these benefits has been ongoing for several years, but recently got a significant boost with the addition of two new assets: an ultrashort pulse laser (USPL) 2,000 times more powerful than the lab’s current instruments, and more importantly, new professional Dr. Brittany Lynn.
Lynn works with Dr. Alexandru Hening, a scientist who has pioneered laser-generated plasma at the Center for five years, and is working on prototypes of lasers used as covert antennas in land vehicles or as radar emitters for submarines. Using plasma has the potential to significantly increase the radar horizon of sensing and communication systems. Lynn plans to develop this technology further, using the newly acquired USPL to create plasmas for deflecting and redirecting electromagnetic and laser weapons.
The new laser achieves 35 femtosecond pulses (a femtosecond is one quadrillionth of a second) at a wavelength of 800 nanometers. The device weighs roughly 440 pounds, compared to the 3,000-pound lasers the Center has used for 20 years.
“With powerful enough lasers you can change the index of refraction of the air, so locally we are manipulating the properties of the air,” Hening said. “If you have a very short pulse you can generate a filament, and in the air that can propagate for hundreds of meters, and maybe with the next generation of lasers you could produce a filament of even a mile.”
Lynn is collaborating with the U.S. Naval Research Laboratory, which does laser modeling, to see how she and the Center could help transition some of that knowledge to the fleet.
“My main goal for next year is to characterize computationally how much power we need in the laser pulse to make these kinds of plasma shields reasonable, how we could make them last longer with a second laser, and looking at a new realm of modeling — how other beams interact with plasmas,” Lynn said.