Abstract

A free-electron laser (FEL) is characterized by very high power levels, high efficiencies, and frequency tunability with output wavelength ranging from millimeter to beyond the optical regime. The FELs are characterized by a relativistic electron beam propagating through a wiggler field, for example, a circularly polarized magnetic field with wavelength λ_w The magnetic wiggler helth caused the electrons to execute circular motion in the direction transverse to the axis of propagation of the electron beam. The Interaction between this transverse motion and the electromagnetic radiatiori can produce a net decrease in the electron-beam energy, if the wavelength of the electromagnetic radiation is ${\text{λ = λ}}_{\text{w}}{\text{/2γ}}_z^2$ where γ_z is the relativistic γ factor of the electron beam in the z direction.

© 1981 Optical Society of America