Military labs test plastic billed as `armor' against lasers

While the Pentagon is busy developing laser weapons, a small California company claims it has discovered a type of plastic that acts as armor against laser energy. The company stumbled on the material by accident and doesn't fully understand why it works. Samples have been sent to several United States military labs, which are running tests to see how strong a laser beam the plastic can withstand.

``We're trying to find out the full magnitude of its capabilities,'' says Slava Harlamor, president of Harlamor-Schadeck Company, which developed the material.

The military applications of an effective laser armor are obvious.

Currently, both the United States and the Soviet Union are working on laser weapons ranging from pistols to giant beams capable of shooting down nuclear missiles on flight. US officials say that Soviet lasers have already been used to dazzle American pilots and early-warning satellites.

The US Strategic Defense Initiative, in particular, is searching for ways to protect space-based weapon and sensor platforms from attack by lasers and other directed energy weapons. Metal-graphite composites, holograph filters, and special heat-absorbing materials are among the shields under investigation by the SDI organization.

Mr. Harlamor's company developed the material, now trademarked ``Laser Shield,'' while searching for a plastic that could be shaped by machine tools yet withstand the stress of aerospace applications.

Researchers first knew they had something unusual when they tried to inscribe the new machinable plastic with an industrial laser-marking system. After 10 passes with this relatively low-power laser, the plastic was unscarred.

``There was no penetration,'' confirms Gerhard Marcinkowski, sales manager of A-B Lasers, which carried out the marking test.

Laser Shield's internal structure apparently acts as if it were made up of many tiny lenses. These internal ``lenses'' can scatter laser energy in a harmless, diffuse pattern.

But Harlamor admits his company does not fully understand Laser Shield's properties. For instance, some tests indicate that as laser power is increased the plastic simply absorbs light energy, instead of reflecting it.

A number of Defense Department laboratories have already run tests on blocks of Laser Shield sent them by Harlamor. The US Army Materials Technology Lab tested a sample last year and confirmed its laser-reflecting qualities, according to an Army spokesman. But the spokesman adds that Laser Shield did not demonstrate capabilities beyond other materials the Army is working on.

The Air Force Strategic Air Command is also sponsoring a series of experiments on the plastic, with the Air Force Space Command looking over its shoulder, according to military officials.