Investigation on Mode Converter Based on All-Dielectric Metamaterial for Gyrotron

Artificial metamaterials have made great progress in controlling and manipulating electromagnetic waves. However, the common plasmonic metamaterials suffer from ohmic loss, which leads to low transmission efficiency and impedes wide application. All-dielectric metamaterials provide an effective means to solve the ohmic loss problem of the plasmonic-type metamaterials. In this paper, a gyrotron quasi-optical-mode converter based on all-dielectric metamaterial is proposed. Such dielectric metamaterial consisting of alumina ceramics and silica substrates is easy to fabricate, making them very promising in developing low-loss terahertz functional devices. The electromagnetic simulation results show that the designed mode converter can well convert the cylindrical TE01 mode into Gaussian beam. The obtained scalar Gaussian content reaches 98.56 % on the observation plane.