Tactical laser weapons still many years away: Air Force solid-state laser program focuses on increasing power levels and beam quality.

• Author: Erwin, Sandra I.

The prospect of highly precise, directed-energy guns has tantalized military planners for decades. But only recently has the Defense Department begun to put real money into laser technology that ultimately could deliver speed-of-light tactical weapons.

Specifically, the Pentagon will spend up to $49 million during the next two years to develop a solid-state high-power laser that could be morphed into a weapon for use on tactical jet fighters, Navy ships or Army trucks.

Lasers are light radiating devices that generally are differentiated by the lasing media, which can be gas, liquid or solid state.

So far, only chemical lasers have achieved the level of power needed for the device to be militarily useful. Examples are the Air Force Airborne Laser--a megawatt-class system installed on a Boeing jet--and the Arm/s ground-based Tactical High Energy Laser. The ABL was designed to shoot down ballistic missiles, while THEL can defeat rockets, mortars and artillery shells.

But chemical lasers--where the energy is created by a chemical reaction--are unpractical as battlefield weapons. They are too big and logistically complex.

Solid-state lasers use crystal or glass as lasing media. They are electrically powered, which makes them attractive for compact weapon systems.

The technology, however, has lagged. Even though solid-state lasers have been around for 30 years, they have not reached the power levels required for a weapon-grade laser. Solid-state lasers are prevalent in low-power applications, such as laser marking and machining.

Generally, a weapon-grade laser would require, at a minimum, power levels starting at tens of kilowatts, up to megawatts.

An industry competition is now underway to develop a 25 kw solid-state laser. The project, managed by the Air Force Research Laboratory, will establish whether the technology is mature enough to warrant further development.

Even if AFRL scientists successfully prove that the 25 kw solid-state laser works in the lab, experts caution, much more development and engineering work would be needed to turn the basic technology into an operational weapon.

Defense contractors such as TRW and Raytheon now claim that a 25 kw solid-state laser is achievable and that, within five to 10 years, they could jack up the power to 100 kw.

The Air Force program was prompted, to an extent, by such claims.

"Contractors have come to us and said they feel they are ready to demonstrate this technology," said Capt. Kalliroi Lagonik, laser physicist at the Air Force Research Lab. "Based on what our scientists know and what the contractors have said, we decided to go ahead and really push that...