April 28, 2020

New Single-Mode THz Dielectric Structure

The development of advanced particle radiation sources and compact accelerators in THz frequency range is one of the promising areas of the long-term cooperation between German and Armenian scientists in the field of accelerator and beam physics, outlined in the declaration signed between DESY and CANDLE during the official visit of DESY delegation to Armenia in autumn 2019.

Dielectric coated structures are one of the leading candidates for future compact linear accelerators and coherent radiation sources in THz frequency range. A joint DESY-CANDLE team investigated the electrodynamic properties of a metal-dielectric waveguide with resistive walls and a dielectric with losses in order to obtain the optimal configuration of the future module for THz radiation and acceleration. It was shown that in the new type of multilayer structure, in comparison with conventional multimode dielectric structures, there is only one synchronous fundamental mode TM01. The research results were published in the April issue of the journal of American Physical Society: Physical Review –Accelerator and Beams (M. I. Ivanyan, L. V. Aslyan, K. Floettmann, F. Lemery, and V. M. Tsakanov, “Wake fields in conducting waveguides with a lossy dielectric channel”, Phys. Rev. Accel. Beams 23, 041301 – Published 22 April 2020)
The new single-mode structure has only one fundamental TM mode, synchronously moving with the charge and having a phase velocity equal to the speed of light. The results are very important from the point of view of both generation of monochromatic coherent THz radiation and stable acceleration, since high-order modes broaden the emission spectrum and negatively affect the beam dynamics. It is planned to carry out experimental studies of the new structure at ARES (DESY) and AREAL (CANDLE) accelerators in order to create a prototype module for future THz coherent radiation sources and high-gradient accelerators.