Abstract

This tutorial describes the advantages, disadvantages, performance, and availability of the free-electron lasers (FELs) now in operation and illustrates their use in medicine, biology, and materials science. Because they use a beam of electrons whose energy can be varied, the wavelength of FELs can be tuned from the far infrared to the ultraviolet; in the future, wavelengths in the soft x-ray region will be available, PELs also produce near-diffraction-limited beams with pulse lengths from the subpicosecond to the multimicrosecond regions and linewidths which are Fourier-transform limited; in the future, cw operation will be possible.

© 1993 Optical Society of America