Abstract

During the past year of oscillator experiments, the Los Alamos free-electron laser (FEL) has demonstrated high-power and diffraction-limited output capabilities with a factor-of-4 wavelength tunability in the IR. The conversion of electron energy into optical radiation occurs within a 1-m long undulator composed of SmCo₅ permanent magnets arranged in a uniform-period plane-polarized configuration. Relativistic electron pulses are supplied by a conventional rf linear accelerator operating at 1.3 GHz with a nominal energy of 20 MeV. Sufficient rf power is supplied to the accelerator to produce a burst of 2000 uniform-current micropulses, each ~40 psec in width and spaced by 46 nsec, the round-trip time of light in the 8.9-m optical cavity. Peak currents in excess of 50 A have been directed through the undulator. The primary experiments, however, were conducted with a peak current of ~30 A, a longitudinal energy spread of 2%, and a transverse emittance of 3π mm · mrad.

© 1985 Optical Society of America