Radiation from Relativistic Electrons in Periodic Structures "RREPS-15"

Transformation of a Symmetrical TM Mode at the Open End of Cylindrical Waveguide with Dielectric Loading

7 Sept 2015, 12:55

15m

Oral 1. General Aspects of Physical Phenomena and Processes Associated with Electromagnetic Radiation 1. General Aspects of Physical Phenomena and Processes Associated with Electromagnetic Radiation

Speaker

Sergey Galyamin (Saint Petersburg State University)

Description

Electromagnetic radiation with terahertz frequencies (0.1-10 THz) is supposed to be a promising tool for a number of applications. Efficient terahertz emission can be achieved, for example, using the beam-driven dielectric loaded structures [1]. Under certain approximations, the problem of transformation of a single TM mode with a high number at the open end of a cylindrical waveguide with a dielectric layer was considered recently [2]. Namely, radiation patterns in the Fraunhofer zone were calculated using rigorous Stratton-Chu formulas, but the field at the outer side of the open end aperture was calculated using Kirchhoff approximation and Fresnel coefficients formalism. In this report, we investigate the applicability of approximations utilized above by considering the rigorous problem statement. We develop the method known for solution of corresponding problem in plane geometry [3] and apply it to the case of cylindrical geometry. This technique is combination of the Wiener-Hopf technique and tailoring technique which leads to the infinite linear system for magnitudes of reflected modes. This system can be solved numerically using the reduction technique. [1] S. Antipov et al., Appl. Phys. Lett. 100, 132910 (2012). [2] S.N. Galyamin et al., Opt. Express. 22(8), 8902 (2014). [3] G.V. Voskresenskii, S.M. Zhurav, Radiotekhnika i Elektronika. 4, 703 (1978).