ISSN - 00189197, IEEE Journal of Quantum Electronics, 1985, vol. QE-21, 7, p. 1023-1025
EFFECTIVE NARROWING OF THE SPECTRAL DISTRIBUTION AT MULTIPLE PASSAGE OF PHOTONS THROUGH A FREE ELECTRON LASER (FEL).
It is shown that the spectral density at the center of the radiation line is effectively increased if the gain of a free-electron laser (FEL) is on the order of unity and when the signal repeatedly passes through an optical cavity because of the nonlinear interaction between harmonics. The action of a FEL is studied for the case of a nonmonoenergetic electron beam.