Jefferson's FEL Generates Unprecedented 155 Watts

To the delight of industry and government investors, the DOE's Thomas Jefferson National Accelerator Facility (Jefferson Lab) achieved 155 W of free electron laser (FEL) light on June 17, making it 15 times more powerful than existing FELs. Vanderbilt Univ. previously held the record with an 11-W FEL.

According to Jefferson Lab's Director Hermann Grunder, researchers celebrated only briefly once the readout indicated 155 W (their initial goal was 100 W). "They couldn't stand celebrating for too long, because they all wanted to get back to work," Grunder explains. "We had a party, but many of the scientists didn't come. They wouldn't leave the lab!"

Jefferson scientists celebrate their accomplishment with champagne on June 17. According to Jefferson Lab's Director Hermann Grunder, the celebration was short-lived because the group was eager to get back to work.

For two years, scientists have been working on developing the Jefferson FEL while the Laser Processing Consortium (LPC) - a partnership between high-technology manufacturers, start-up companies, research universities, government, the Commonwealth of Virginia, and the U.S. Navy - helped fund the laser's approximately $25 million price tag.

Industry is interested in high-power FELs because they are tunable, and the power they could generate might make them cost-effective solutions for such applications as marking, cutting, micromachining, and surface processing. The "holy-grail" for manufacturers is an FEL that produces powerful UV light in the kilowatt power range. And that's what Jefferson Technology Transfer Manager Fred Dylla says the Jefferson Lab hopes to eventually achieve.

But so far, 155 W of power in the IR is what they're producing, and companies will start putting that to use. "We have collaborations with companies that can begin experiments at 155 W. The idea is that for the next six months we continue upgrading the FEL and running experiments off of what we have," explains Grunder.

According to Michael Kelley of DuPont Central Research and Development, the company will use the FEL for experiments involving the microroughening of polymer surfaces and ways to make polymer surfaces electrically conductive.

"DuPont had a research program that looked at the modification of polymer surfaces with laser light, but it became very expensive" says Kelley. "Jefferson contacted a number of companies looking into possible collaborations, and it made more sense to share facilities than to spend money and do it completely alone."

In addition, other companies such as Armco, Northrop-Grumman, and Virginia Power will begin experimenting with metals processing. Six laboratories will be housed in a 20,000 sq ft building that sits above the FEL, which resides in the basement. Dylla explains that the laser light will be carried up to the labs through an already operational optical transport system.

According to Dylla, the system transports laser light from the FEL through a pipe under vacuum, using high-quality mirrors. Once the light reaches the second level of the building, it continues down the length of the floor. A pipe runs into each of the laboratories, where mirror assemblies interrupt a selectable fraction of the light, determined by how much the companies want to use.

In addition to the research labs in the building where the FEL resides, universities such as Old Dominion, the College of William and Mary, Christopher Newport, and Norfolk State will be housed in an Applied Research Center - an $18 million building built by the City of Newport News - that sits adjacent to the lab.

History of the facility

The Jefferson FEL is the product of a lab primarily created to conduct basic research on the atom's nucleus. The $600 million facility, initially called the Continuous Electron Beam Accelerator Facility (CEBAF), opened in 1994, its name changed in 1996. Scientists quickly realized that the powerful beam their accelerator facility produced could be used to create an FEL of substantial power, and in 1996 development of the laser got underway. Industry and government agencies quickly invested in the project, forming the LPC.

Other FELs

There are less than 20 FELs worldwide at institutions such as Duke, Stanford, Vanderbilt, the Univ. of Calif. at Santa Barbara, and the CLIO facility in France. But as mentioned earlier, their power level has yet to exceed 11 W.

While industry has less use for low-power FELs, these lasers prove to be excellent research tools for solid-state and molecular physics, medicine, and the biosciences. Bob Guenther, interim director of Duke Univ.'s FEL laboratory, explains that Duke's FEL is used primarily for medical research. "Researchers are using the laser to study wound healing, tissue welding, and cornea sculpting," he says. "They also study retinal and nerve cutting. In all of these cases, they're looking at the healing process of the laser. We are searching for wavelengths that produce a minimum of collateral damage so that the healing process will produce minimum scarring and increase the probability of recovery of full function."

Trend-setting?

Dylla hopes that as the laser continues to develop, more companies will express an interest in becoming part of the consortium. "When we start to get positive feedback from the companies that are already involved, other companies may join in. Three companies that are part of the consortium hope to have initial experimental results later this year. That's when other people become interested, when they see what these companies are doing."

Grunder says that the LPC will serve as an example to other groups that want to pursue a similar collaboration. "We think that this will be the start of a trend. Of course, there is still some skepticism. People want to know if the laser is running, if it is running reliably, and if it can be extrapolated to higher levels. We believe we know these answers, but this is still an experiment. If we are successful, it will have quite an impact."

For downloadable photos and additional text, please consult http://www.jlab.org/FEL/FELpics/FirstLight/FirstLight.html.