Three-dimensional theory of the Cerenkov free-electron laser

Abstract

We present an analytical theory for the operation of a Cerenkov free-electron laser which includes diffraction of the optical mode in the direction transverse to the electron beam. Because the width of the optical mode depends on gain, the usual cubic dispersion relation is replaced by a 5/2-power dispersion relation, which allows two roots. These roots both have positive real parts, indicating that they are slow waves. For a narrow electron beam, the optical mode is much wider than the beam, thus reducing the gain by an order of magnitude from that predicted by the two-dimensional theory. In the limit of a wide electron beam, the two-dimensional theory is recovered.

Optical emission from a high-refractive-index waveguide excited by a traveling electron beam

“…2,[11][12][13][14][15][16][17][18][27][28][29][30][31] The term "classical" in this section means that the electron is regarded as a spatially localized point particle. On the other hand, "quantum mechanical treatment" means to regard the electron as a wave spreading in space, whose spreading range is the size of an electron as well as the coherent length of an electron wave.…”

“…3,4 The Cherenkov laser has the possibility of operation at a relatively low voltage with a compact size. [12][13][14][15][16][17][18][19][20][21] Radiation of an electromagnetic wave at approximately 100 GHz from a Cherenkov laser with an electron acceleration voltage of 35-75 kV has been reported. 19 However, radiation in the optical frequency range obtained from a Cherenkov laser has not yet been observed.…”

“…[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] These devices utilize the kinetic energy of an electron beam in a vacuum, and the condition required to obtain the radiation and to amplify the electromagnetic wave is that the velocities of the electron beam and the electromagnetic wave coincide. Therefore, these devices can operate, in principle, over a very wide frequency range extending from the microwave to the x-ray regions of the electromagnetic spectrum.…”

Simulation analysis of rectangular dielectric-loaded traveling wave amplifiers for THz sources

“…Various linear theories have been developed to analyze beam-wave interaction in dielectric-loaded structures [22,23]. In this section, an alternative linear theory is presented, that is developed by introduction of an effective dielectric parameter for the beam channel, and then particle simulations for a cold beam are used to check the linear theory.…”

Slow Electromagnetic Waves: Theory and New Applications

“…A quantitative analysis can be conducted by using the mode expansion of the electromagnetic field in the waveguide matched to the Fourier expansion of the source current [6].…”