DURHAM, N.C. -- A record-setting Russian ultraviolet free-electron laser
(FEL) has begun operating at its new home at Duke University, where investigators
expect to harness it soon for medical research such as improved laser surgical
techniques.
The device also is producing intense beams of gamma rays, which other physicists
hope will help answer major questions in nuclear physics such as understanding
thermonuclear processes inside stars like the sun.
The OK-4 optical klystron FEL, originally developed at the Budker Institute
of Nuclear Physics in Novosibirsk, Russia, was moved to Duke in May 1995
to take advantage of a much more powerful 1.1 billion electron volt electron
"racetrack" at Duke's Free-Electron Laser Laboratory.
After being reassembled and joined to the laboratory's electron ring, the
OK-4 began producing ultraviolet laser light late on Nov. 13. Within two
days, physicists had also induced the system to produce gamma rays by colliding
the laser beam with the same electron beam that feeds it.
Duke's FEL Laboratory is funded by a U.S. Department of Defense program
for advancing laser technology in medicine.
Free-electron lasers are like no others because they produce laser light
by perturbing beams of "free" electrons that have been liberated
from their normal bondage to atoms. Because electrons that provide the energy
of other lasers are held within the structure of their atoms, such lasers
can emit only a limited number of discrete wavelengths of light. FELs, in
contrast, can be "tuned" to a large variety of different wavelengths.
Also, FELs' beam pulse structures and power levels are extremely easy to
manipulate.
FELs produce light by passing such free-electron beams through a series
of magnets. As in all lasers, the energized electrons emit light, which
is then amplified and concentrated into a sharp beam by rapidly bouncing
the light between mirrors within an "optical cavity."
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Contact: Monte Basgall
basgallm@mail01.adm.duke.edu
919-681-8057
Duke University
21-Nov-1996