The Hottest Light Show Around (Daily Press)

The Hottest Light Show Around

Scientists line up to try out Jefferson Lab's free-electron laser

by Tom Fredrickson, Daily Press
October 3, 1999

Newport News - It dices. It slices. It even glazes and drills.

No, it's not a Ronco kitchen gadget; it's the world's most powerful free-electron laser. And scientists representing some of the largest corporations in America are lining up to try it out at the Thomas Jefferson National Accelerator Facility.

The technology offers the potential for comfortable wrinkle-free clothes, maneuverable spacecraft flying to the outer planets of the solar system and computer hard drives with awesome memory capacity.

All this from an invisible beam of light.

In July, Fred Dylla and his team at Jefferson Lab delivered on his promise of making a laser of at least 1 kilowatt in strength. The laser delivered 1.7 kilowatts of power, 150 times more than the old free-electron laser record achieved at Vanderbilt University in Nashville, Tenn.

To the electrically minded, 1.7 kilowatts might not sound like much - it's only the power of 17 100-watt light bulbs. But that's just an average power. The laser's power actually is millions of watts during the flickering instants when the pulsing light is on. That's enough power to burn quickly through virtually any material.

The laser works. Now, engineers must figure out how to steer the beam more effectively and capture more of its power as the light shoots from the underground laser tunnel, bounces off a series of mirrors and is delivered to materials being tested in the 6,000 square feet of lab space overhead.

In August, corporate and university researchers conducted about two dozen experiments at the laser facility's six labs. The next batch of experiments will take place this month.

"We realize we need to make further adaptations," said Michael Kelley, chairman of the Laser Processing Consortium at Jefferson Lab. "There is a learing curve here."

The real commercial promise for the laser may lie in boosting its power 10-fold, taking it from the infrared into the ultraviolet part of the light spectrum. That could make it useful for working on a host of new materials.

The power boost, which depends on additional funding from Congress, would permit 10 times the power at a cost five times lower per kilowatt, making the laser more attractive for commercial and potential defense uses than competing technologies.

The military is interested because of the laser's Star Wars potential of passing through clouds and disabling the guidance systems on missiles homing in on U.S. targets.

Some predict the lab will attract high-tech service companies that will help other companies run tests.

Longer term, the laser's commercial viability depends on the creation of industrial lasers that could be purchased and used at off-site plants. The commercial laser is five to seven years away.

Northrop Grumman and Newport News Shipbuilding officials want their companies to team up to make the commercial lasers.

Who would buy the multimillion-dollar machines? Potentially, some of the same companies that want to use the lab for testing.

So many researchers want to use the new laser that lab time is limited, said Greg Kessel, an engineer at Virginia Power. He managed to squeeze in an eight-hour experiment.

Virginia Power is working with Armco, a specialty steel producer, to see if the laser can be used to smooth out microscopic fissures that naturally occur between metal crystals.

The electric utility is interested because it has thousands of turbine blades made from costly steel alloys. Some of the blades last for decades; others must be replaced after a few years as oxides and other impurities corrode and weaken the metal.

Virginia Power has 27 turbines, which spin under steam pressure to run generators. Each turbine has 40-50 rows of turbine blades that cost between $150,000 and $2.5 million per row.

"Many times, if we can improve the life of a blade, we can save $1 million per row," Kessel said.

Virginia Power's experiment so far hasn't been successful. At low levels of power, the laser couldn't melt the metal enough to seal the fissures. And at higher temperatures, the laser couldn't be steered precisely.

Armco engineers are working out a process to improve the steering, and the companies are scheduled to return to the lab this month to try it out.

The idea is to use the laser to melt the top layers of molecules. Other lasers could perform the same work. But the free-electron laser potentially can do it in a fraction of the time because its powerful beam does its melting in pulses lasting a trillionth of a second.

Another company, DuPont, is using the laser to test a procedure for improving "sails" on spacecraft.

The work on the solar sail consists of using the laser to drill holes into a special polymer that's been used successfully in space. The experiment was done in partnership with Northrop Grumman, Jefferson Lab, and NASA.

NASA plans to use solar wings, made lighter by laser drilling, to power and maneuver long-distance spacecraft and satellites. The wings work much like a sail on a boat, except photons of light, not wind, push the craft.

During testing, the laser produced holes that "weren't pretty," but the tests showed the technology is feasible, Kelley said. The laster processing consortium chairman used to work for DuPont. He now splits his time between the lab and the College of William and Mary, where he teaches applied science.

A unique feature of the laser makes it ideal for working on composite materials such as the solar sail. The laser's infrared wavelength can be fine-tuned. The laser passes right through some materials at certain frequencies.

This property allows the light to drill through the polymer layer on a solar sail but not penetrate the sail's reflective aluminum layer.

Closer to home, DuPont is testing surface conditioning to make polyester feel like cotton. The country's largest manufacturer of chemicals, fibers and plastics tested the laser's ability to make tiny slits to break up the long strands of polyester.

Kelley was unable to get the lab apparatus to work just right to condition the polyester how he wanted.

"We do our experiements, and our computer molels tell us where to go and look, but we need to do trial and error also," Kelley said.

Among the glitches: the light's beam was slightly off target, causing some aluminum equipment in the lab to glow red. The shape "go distorted. It was not that far from the puddle stage," Kelley said.

Because of the dangers of the beam - it can blink you in an instant - researchers conduct the tests in other rooms via TV monitors.

Aerospace Corp., which gets 90 percent of its research contracts from the Air Force, is waiting for its turn in the lab. Scientists there want to try "micro-machining" ceramics and silicon materials for use in micro-thrusters to guide five-inch diameter satellites that could be deployed in space in the next few years.

"To make a little rocket nozzle out of silicon is not trivial," said Henry Helvajian, senior scientist at Aerospace Corp. "With ceramics, it's even harder."

The satellites' micro-thrusters need to be fashioned into an hourglass shape to keep fuel from being released too quickly - only a small volume of fuel can be stored on the tiny satellites.

When mass-produced, the satellites - picture large hockey pucks - will be arrayed for use as relatively low-cost communications satellites. Launching them will be cheaper than shooting off bigger, heavier satellites. They'll also be used as disposable probes to check out exterior flaws on other satellites and space shuttle.

Many other experiements are in process. An assistant professor of physics at the College of William and Mary is studying the laser's ability to condition multiple layers of magnetic metals, giving the potential for computer disk drives with enhanced memory.

For Fred Dylla, who made his first laser at age 13, it's still just the beginning.

Facts and Figures About Lab's Free-Electron Laser