Theory of terahertz Smith-Purcell radiation from a cylindrical grating

  • Z. Rezaei Department of Physics, Faculty of Science, Arak University, Arak, P.O. Box 38156-8-8349, Iran
  • B. Farokhi Department of Physics, Faculty of Science, Arak University, Arak, P.O. Box 38156-8-8349, Iran
Keywords: Smith Purcell radiation, cylindrical grating, dielectric, terahertz radiation

Abstract

An analysis of an annular electron beam propagating along a cylindrical grating with external magnetic field Bo is presented. The grating comprises a dielectric in its slots. The dispersion relation of the modes is derived. The results demonstrate that the dielectric shifts the frequencies of the system modes to smaller values. The growth rates of the modes which are in phase with the beam are also considered. It is found that the decline in the growth rate is brought about by the dielectric. In addition, increasing the thickness of the dielectric and decreasing the height of the slots cause it to rise. The effect of beam thickness on growth rate is considered too. This is shown to increase and then fall as beam thickness increases. These results show that utilizing cylindrical grating loaded with dielectric has a promising effect on developing new kinds of compact high-efficient THz free-electron lasers based on Smith–Purcell radiation.

Edited by: A. B. Márquez

Published
2019-10-08
How to Cite
Rezaei, Z., & Farokhi, B. (2019). Theory of terahertz Smith-Purcell radiation from a cylindrical grating. Papers in Physics, 11, 110007. https://doi.org/10.4279/pip.110007
Section
Articles