Free-electron lasers driven by RF linacs

A free-electron laser consists basically of an accelerator to produce the electron beam, a 'wiggler' magnet to force the electrons to oscillate and radiate, and an optical system to form the laser beam. Compared with conventional lasers, free-electron lasers, particularly those driven from RF linacs, possess several important advantages. Thus, they offer broad tunability across the optical region. RF linacs have been employed to operate free-electron lasers at wavelengths from 40 microns to 1.6 micron. Another important advantage of free-electron lasers is related to their very high optical-beam quality. Attention is given to questions regarding the experimental status of free-electron lasers driven by RF linacs, and a variety of new developments, including a broader range of wavelengths, higher efficiency, and higher power.