Smith-Purcell free electron laser based on the semi-elliptical resonator

Abstract

A novel Smith-Purcell (S-P) free electron laser composed of an electron gun, a semi-elliptical resonator, a metallic reflecting grating and a collector, is presented for the first time. This paper studies the characteristics of this device by theoretical analysis and particle-in-cell simulation method. Results indicate that tunable coherent S-P radiation with a high output peak power at millimeter wavelengths can be generated by adjusting the length of the grating period, or adjusting the voltage of the electron beam. The present scheme has the following advantages: the semi-elliptical resonator can reflect all radiation with the emission angle θ and random azimuthal angles, back onto the electron beam with same-phase and causes the electrons to be modulated, so the output power and efficiency are improved.

Interaction of electron beams with optical nanostructures and metamaterials: from coherent photon sources towards shaping the wave function

“…The possibility of tuning the wavelength of the emitted light by either changing the period of the grating or the velocity of the electron has made the Smith-Purcell effect one of the prominent choices for designing THz radiation sources [122,123], in addition to superconductors [124]. In general, the Smith-Purcell effect is routinely used to design tunable electromagnetic sources in frequency and power ranges which are not directly accessible by semiconductor-based lasers [107,108,[125][126][127][128][129][130][131][132][133][134][135]. Smith-Purcell radiation is one of the different mechanisms for designing free electron lasers, besides bremsstrahlung and Thomson scattering [136].…”