Laser Amplification by Electron Beams

This paper describes a klystron amplifier designed to operate at optical frequencies. The theory of the interaction between light waves constrained by thin, rectangular light guides and transverse electron beams is considered. The electron beams are shown to be velocity modulated at emergence from the intense E field in the first pipe. Bunches are allowed to form and the bunched beams are passed across a second light pipe in which they induce an amplified light signal. The quantum theory of the interaction has been compared with the classical interaction theory. The comparison shows that the two theories are identical, except for a quantum term of order h¿/muo 2, which is negligible for the numerical values of our design. Thus, in our case quantum and classical theories lead to identical results.