Lasers

Ultraviolet Lasers that can Stun a Person or Freeze Him in His Tracks

Laser Device May Provide U.S. Military Nonlethal Option
by David Mulholland
Defense News Staff Writer

Source: HSV Technologies, Inc.
http://www.hsvt.org/Defensenews.html

June 14, 1999

Washington -- A device that can stun a person or freeze him in his tracks may no longer be the exclusive domain of science fiction, if a new idea in non-lethal weapons reaches development.

The invention uses ultraviolet lasers to create channels of ionized air leading to the target, along which a high-voltage current can be transmitted for distances as great as 100 meters.

Created by HSV Technologies, Inc., of Lakeside, Calif., the idea has been sent to the Pentagon's Joint Non-Lethal Weapons Programs Directorate, Quantico, Va., for its annual call for new ideas.

The Directorate will announce which technologies it will pursue at the end of June, according to Directorate officials.

While there is some debate over the intensity of the lasers needed to create electrically conductive ionized channels in the air, HSV and outside officials said the lasers will be weak enough to cause only slight skin or eye irritation.

International humanitarian and non-governmental groups may contest that assertion, as they vehemently oppose laser-based non-lethal weapons on grounds they cause permanent damage to the eye.

The ultraviolet laser's goal is similar to the taser. But instead of using the latter's gunpowder-launched metal darts that trail wires to carry the charge, the Anti-Personel Beam Weapon (APBW) uses lasers to create electrically conductive channels [through the air]. This allows the device to project a variety of electrical charges.

When air is ionized, it turns into a plasma, which shares many of the electrically conductive properties of metals. By using lasers to create a positively charged conduit and a negatively charged one, the APBW can set up an electrical circuit with current running through the target, according to the patent for the device.

At the lowest setting, the charge would mimic the electrical impulses that the brain uses to contract muscle tissue. Eric Herr, [the] APBW's inventor and vice president of HSV, said a blast at this level would cause a person's [skeletal] muscles to contract, effectively freezing him in place.

But other charges could be used like a taser to stun someone, kill them by causing their heart to stop beating, or even halt vehicles by shorting their electrical systems.

A device with such capabilities is what the U. S. military has been looking for, said a Non-Lethal Weapons Programs Directorate official who requested anonymity. Richard Scheps, a senior researcher with the U. S. Navy's Space and Naval Warfare Systems Command, San Diego, said the idea "has a lot of viability." Scheps is not involved in the program, but has examined the patent and experimental results. If the concept is successful, Herr estimates that the device [eventually] could be produced for about $50,000 each and would be about the size of a carry-on suitcase.

The ideas for using various electric currents to achieve the results specified in the patent are well known, as is the use of lasers to ionize air, said university and government researchers. But the power required for the lasers to create electrically conductive channels is the subject of some debate.

"Once air is ionized, it is a very good conductor," said Ambrogio Fasoli, assistant professor of physics at the Massachusetts Institute of Technology's Physics Department Plasma Science and Fusion Center, Cambridge, Mass. "But you need a powerful laser with a good beam size."

"I certainly would not stand in front of it," he added. Herr, however, argued that the type of laser used allows it to create minimally damaging energy. In experiments at the University of California at San Diego, Herr said he was able to pass a current through a plasma conduit that was weak enough for him to put his hand into the beam, causing only minor discomfort similar to a sunburn.

Scheps said that the device could incorporate a rangefinder to tailor the beam's strength to the target distance for the minimum power needed to maintain the plasma channel.