Free-Electron Laser senior research scientists Steve Benson (left) and David Douglas tune up the FEL hardware in preparation for a 10 kilowatt run. Photo by Greg Adams, JLab.

Newport News, Va. - The Free-Electron Laser (FEL), supported by the Office of Naval Research and located at the U.S. Department of Energy's Thomas Jefferson National Accelerator Facility, achieved 10 kilowatts of infrared laser light in late July, making it the most powerful tunable laser in the world. The recently upgraded laser's new capabilities will enhance defense and manufacturing technologies, and support advanced studies of chemistry, physics, biology, and more.

The Free-Electron Laser vault at Jefferson Lab showing the superconducting accelerator in the background and the magnetic wiggler in the foreground. The wiggler converts the electron beam power into laser light. Photo by Greg Adams, JLab.

"No other laser can provide the same benefits to manufacturing, medical research, biology, and basic physics," said ONR's Directed Energy Program Officer, Mr. Quentin Saulter. "The Navy has chosen the FEL because it has multi-mission capabilities. Its unique, high-power and 24-hour capabilities are ideal for Department of Defense, industrial, and scientific applications."

The Free-Electron Laser Upgrade Project is funded by the Department of Defense's Office of Naval Research (ONR), the Air Force Research Laboratory, the US Army Night Vision Laboratory and the Joint Technology Office with the cooperation of DOE's Office of Science. The project includes plans to improve the machine's ability to produce infrared (Navy), ultraviolet (Air Force) and terahertz (Army) light. The FEL plans to produce experiment-quality terahertz light by late summer, and the ultraviolet portion of the upgrade is slated for completion in the spring of 2005.

The FEL program began as the One-Kilowatt Demonstration FEL, which broke power records and made its mark as the world's brightest high average power laser. It delivered 2.1 kilowatts (kW) of infrared light, more than twice it was initially designed to achieve, before it was taken offline in November 2001 for an upgrade to 10 kW. "Whenever a technology gains a factor of ten improvement in performance, the achievement opens the door to many new applications, some foreseen, and some are simply very pleasant surprises," said Christoph Leemann, Jefferson Lab Director. "We look forward to operating this exciting new machine and carrying out the many experiments planned for it."

The One-Kilowatt Infrared Demonstration FEL operated for two and a half years and broke all existing power records for tunable high-average power lasers. It was used for a variety of applications by researchers representing more than 30 different groups, including the Navy, NASA, universities and industry.

The FEL provides intense beams of laser light that can be tuned to a precise wavelength, and which are more powerful than beams from a conventional laser. Conventional lasers are limited in the wavelength of light they emit by the source of the electrons (such as a gas or crystal) used within the laser. In the FEL, electrons are stripped from their atoms, then whipped up to high energies by a linear accelerator. From there, they are steered into a wiggler, a device that uses an electromagnetic field to shake the electrons, forcing them to release some of their energy in the form of photons. As in a conventional laser, the photons are bounced between two mirrors and then emitted as a coherent beam of light. However, FEL operators can adjust the wavelength of the laser's emitted light by increasing or decreasing the energies of the electrons in the accelerator or the amount of shaking in the wiggler.

Other experiments planned for the first year of operation include the fabrication of carbon nanotubes by NASA scientists; the study of hydrogen defects in silicon and pulsed laser deposition of materials by College of William and Mary researchers and photochemistry and photobiology investigations by researchers from the University of Virginia and Princeton University.

"As we cross the 10 kW milestone, our team at Jefferson Lab is grateful for the considerable support and encouragement we have received from the Navy, Air Force and our colleagues across the country," said Fred Dylla, Jefferson Lab FEL program manager.

ONR's Quentin Saulter manages the FEL development effort in cooperation with the Naval Sea Systems Command (NAVSEA) Directed Energy and Electric Weapons Office, headed by Captain Roger McGinnis. ONR is also funding the operation and optimization of the 10 kW FEL, and has several experiments slated to begin in early fall. A laser materials damage study will be co-funded with the Office of the Secretary of Defense High Energy Laser Joint Technology Office (HEL-JTO). In another project, scientists from the Naval Research Laboratory will study laser propagation through the atmosphere, with an eye to new laser-based shipboard defense strategies.

During the upgrade process, FEL staff installed new optics, more accelerating components, new power supplies in the injector and a new wiggler that enables an electron beam to produce laser light. These improvements increased the linear accelerator energy 300% (from 40 to 160 million electron volts), doubled the machine's achievable current and made it possible for the optics to take a ten-fold increase in power.

The Navy is also interested in the ultraviolet and terahertz light that the FEL can produce at world-record powers. The Navy intends on using the lessons learned from the development of the 10 kW FEL to begin design and construction of a 100 kW FEL over the next four years. Eventually, the Navy plans on moving the 100 kW laser to an over water test site and scaling the power up to megawatt levels.

• Office of Naval Research Release
• News Release: Upgraded FEL Produces First Light
• Jefferson Lab FEL Program
• FEL IR Demo Achieves First Light
• FEL Research Overview
• FEL Research with T-rays
• FEL Carbon Nanotubes Research
• Innovations Report: Free-electron laser reaches 10 kW
• Azom: Free-Electron Laser Achieves 10 Kilowatts of Infrared Laser Light
• Navy News: ONR - Supported Free-Electron Laser Most Powerful Tunable Laser in World
• Daily Press: Jefferson Lab beats record for laser
• Daily Press: Jefferson Lab laser beats own record
• Front Page Image: 10kW ship

To enable experimenters to probe deep inside the atom's nucleus with electrons, Jefferson Lab pioneered superconducting technology for accelerating electrons to high energy in efficient, cost-effective accelerators. Jefferson Lab's superconducting electron-accelerating technology offers two commanding cost advantages for FELs: the laser can stay on 100% of the time instead of only 1% or 2% and more than 90% of the energy that is not converted to useful light in a single pass can be recycled.

For additional information, contact Thomas Jefferson National Accelerator Facility (Jefferson Lab), Newport News, Virginia or the Office of Naval Research: