Abstract-High power THz coherent Cherenkov radiation based on a separated dielectric loaded waveguide

Shimin Jiang, Weiwei Li, Zhigang He, Ruixuan Huang, Qika Jia, Lin Wang, Yalin Lu,



https://www.sciencedirect.com/science/article/pii/S0168900219301202

In this paper, we propose a new type of dielectric loaded waveguide structure named separated dielectric loaded waveguide (SDLW), whose dielectric layer and metal layer are separated with each other. The characters of wakefield inside SDLW are studied in details by theory analysis and numerical simulation. Compared with the ordinary dielectric loaded waveguide, the peak power of Terahertz coherent Cherenkov radiation (CCR) excited by the short relativistic electron bunch can be enhanced by over one order. Therefore, this new structure offers a promising candidate for high power THz source

Abstract-Design of a Pre-Bunched THz Free Electron Laser

Ruixuan Huang, Weiwei Li,  Zhouyu Zhao, Heting Li, Jigang Wang, Tian Ma, Qiuping Huang, Zhigang He, Qika Jia, Lin Wang, Yalin Lu

https://www.mdpi.com/2571-712X/1/1/21/htm

Terahertz (THz) radiation has attracted much attention in new scientific and industrial applications. There has been significant recent progress in generating THz with accelerators. To investigate the collective behavior of electron dynamics, we have proposed a new high throughput material characterization system, which supplies a multiple light source. The system includes a pre-bunched THz free electron laser (FEL), which is a high-power narrow-band THz source with a wide tuning range of frequency. The physical design with the main components of the facility is introduced, and the simulation results are illustrated. Radiation of 0.5–3.0 THz is obtained by the fundamental wave of the pre-bunched beam, and radiation covering 3.0–5.0 THz is realized by second harmonic generation. As the simulation shows, intense THz radiation could be achieved in a frequency from 0.5–5.0 THz, with a peak power of several megawatts (MWs) and a bandwidth of a few percent.

Abstract-Harmonics generation of a terahertz wakefield free-electron laser from a dielectric loaded waveguide excited by a direct current electron beam

Weiwei Li, Yalin Lu, Zhigang He, Qika Jia, and Lin Wang
https://www.osapublishing.org/ol/abstract.cfm?uri=ol-41-11-2458

We propose to generate high-power terahertz (THz) radiation from a cylindrical dielectric loaded waveguide (DLW) excited by a direct-current electron beam with the harmonics generation method. The DLW supports a discrete set of modes that can be excited by an electron beam passing through the structure. The interaction of these modes with the co-propagating electron beam results in micro-bunching and the coherent enhancement of the wakefield radiation, which is dominated by the fundamental mode. By properly choosing the parameters of DLW and beam energy, the high order modes can be the harmonics of the fundamental one; thus, high frequency radiation corresponding to the high order modes will benefit from the dominating bunching process at the fundamental eigenfrequency and can also be coherently excited. With the proposed method, high power THz radiation can be obtained with an easily achievable electron beam and a large DLW structure.

© 2016 Optical Society of America

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Abstract-Broad-tunable terahertz source with over-mode waveguide driven by train of electron bunches

Weihao Liu, Yalin Lu, Zhigang He, Weiwei Li, Lin Wang, and Qika Jia

A broad-tunable free electron terahertz radiation source is proposed. In this source, a train of electron bunches with tunable bunching frequency is produced by a photocathode based DC-gun under excitation of a train of tunable laser pulses. These electron bunches are then applied to excite an over-mode waveguide, in which diverse guided modes are coupled into radiation with frequency determined by the bunching frequency. By this means, the tunable radiation with frequency extending from 0.1 THz to 1.2 THz can be obtained from one single structure model. In addition, compared with other sources, the proposed source is compact and easily achievable.

© 2016 Optical Society of America

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