Broadband Tunable Pre-Bunched Electron Cyclotron Maser for Terahertz Application

Abstract

The relativistic electron cyclotron maser (ECM) has been successfully applied to generating high-power THz wave. In order to realize the additional advantages of broadband tuning and high efficiency interaction, this paper is devoted to exploring the THz pre-bunched ECM. Other than a conventional open-cavity tunable gyrotron consecutively switching between axial modes to realize frequency tuning, a pre-bunched ECM system operates on the backward traveling-wave resonance to achieve broadband smooth tuning. Especially, an interaction circuit of specified axial profile of beam-wave detuning frequency is built to achieve high efficiency. An optimized 0.1 THz pre-bunched ECM system using an electron beam of 30 kV voltage and 3 A current is predicted to generate broad bandwidth of 10 GHz and efficiency between 10% 25%. The broadband tuning pre-bunched ECM is promising for a new generation of broadband and high-power THz source.Index Terms-Broadband tuning, coherent radiation, electron cyclotron maser (ECM), terahertz (THz).

High-Efficiency Excitation of a Third-Harmonic Gyrotron

“…The perfect-matched layer is loaded at both ends of the cavity, which would exponentially reduce the field strength by imposing an energy absorbing termJ abs . The reliabilities of both codes were verified in a series of previous publications [35], [38], [39].…”

Theoretical Study of a ${W}$ -Band-Covering Frequency-Tunable Gyrotron

“…EM sources in the millimeter waveband can be divided roughly into two classifications, i.e., electronic devices and optical devices. Though optical devices such as optically pumped lasers and quantum cascade lasers can output energy of very-high-frequency EM waves, its output power is likely at most to be the milliwatt level [5]. In the millimeter and submillimeter wave band, a type of vacuum electronic device called the gyrotron, which is based on the principle of the electron cyclotron maser (ECM), has sufficient capacity to generate high-power radiation with high efficiency [5], [8], [9].…”

Broadband THz gyrotron based on a pulse magnet

“…HZ radiation generated by gyrotron is applied to drive the dynamic-nuclear-polarization (DNP) enhanced NMR, which would greatly increase the high-field NMR sensitivity and bring revolution to the biomedical and material research [1]. Until now, the gyrotron is the best available high-power THz source to drive DNP-NMR system.…”

“…Until now, the gyrotron is the best available high-power THz source to drive DNP-NMR system. Furthermore, gyrotron with broadband capability is especially attractive for a series of advanced applications [1][2][3][4].…”

“…In order to improve the tunable frequency bandwidth, the THz gyrotron reported in this paper selects a backward-wave interaction circuit to replace the traditional open cavity circuit [1]. The system design is shown in Fig.…”