Generating 0.42 THz radiation from a second harmonic gyrotron

Abstract

Gyrotrons are high powered coherent electromagnetic radiation sources, and are considered to be available powerful sources that have the potential to bridge the so-called terahertz gap. In the University of Electronic Science and Technology of China, a second harmonic gyrotron has been designed, manufactured, and tested. The gyrotron generated radiation at a 0.423 THz frequency in 5 s pulses with an 8.1 Tesla magnetic field, with a power per pulse of about 4.4 kW. To date this is the highest frequency recorded for vacuum electronic devices in China. The gyrotron design, operation and measurements are presented. Terahertz (THz) waves, electromagnetic radiation between far infrared and millimeter wavelengths, have very important academic and application values. The characteristics of THz waves are used in a large and increasing number of applications. These applications include fundamental scientific research (physics, chemistry, etc.), many interdisciplinary fields (biophysics, etc.), radar, communication, material processing, and medical diagnostics and therapy. However, because there is a lack of reliable sources and detectors of terahertz radiation, most applications are still experimental. Consequently, current investigations on terahertz waves are concentrated on sources (electronics sources and optical sources), detectors, transmission, and applications [1,2]. In China, terahertz waves have become an active research area over the last 10 years [3,4]. Important achievements have been made, such as the THz vacuum electronic devices developed in the University of Electronic Science and Technology of China [5,6], the THz quantum cascade lasers (QCL) developed in the Shanghai Institute of Microsystem and Information Technology [7,8], the THz superconducting detector in the Nanjing University [9,10], the THz optical sources research carried out in Tianjin University [11] and Nankai University [12], the THz time-domain spectroscopy methodology and related application researches carried out in the Capital Normal University [13,14], the THz-material interaction carried out in the Shanghai Jiao Tong University and Institute of Physics, Chinese Academy of Sciences [15], and so on [1618].In this paper, we report on initial experiments on a second harmonic gyrotron developed at the University of Electronic Science and Technology of China (UESTC), which generated radiation at a frequency of 0.423 THz in 5 s pulses, with a power per pulse of about 4.4 kW. To date this is the highest frequency recorded for vacuum electronic devices in China.Gyrotrons are fast-wave vacuum electronic devices, based on the interaction of electronics gyrating in external magnetic fields with fast waves. There is no need for the slow-wave circuits used extensively in traditional vacuum electronic devices. Gyrotrons can have physical dimensions much larger than the operating wavelength, so they have higher output power and higher efficiency than traditional vacuum electronics devices [19]. Therefore, they are considered to be available powerf...

High-power TM 01 millimeter wave pulse sensor in circular waveguide

“…There have been extensive demands on the compact highpower millimeter wave sources due to their unique physical properties for numerous applications, including in radars, communications, plasma heating, and in a directed-energy weapon. [1,2] So far, gyrotrons [3][4][5] and relativistic Cerenkov oscillators [6][7][8][9][10] have shown the merits of compactness and high-power up to the MW level. Circular waveguides are widely used in these two types of sources to generate and propagate high-power millimeter wave pulses of TE or TM mode.…”