Miniature Slow-wave Free-electron Laser

Yen-Chieh Huang^1*, Po-Hsun Wu², Hossein Shirvani¹, Po-Wei Kuo¹

¹Institute of Photonic Technologies, National Tsing Hua University, Hsinchu, Taiwan
²Department of Physics, National Tsing Hua University, Hsinchu, Taiwan

* Presenter:Yen-Chieh Huang, email:ychuang@ee.nthu.edu.tw

A free-electron laser (FEL) generates coherent electromagnetic radiation from energetic electrons in a vacuum. Generally, an FEL device can be divided into two categories, the fast-wave FEL adopting a relativistic electron beam in an undulator and the slow-wave FEL adopting a sub-relativistic electron beam in a slow-wave structure. The latter is relatively compact because a low-energy electron beam from a small accelerator can synchronously transfer its kinetic energy to a slow wave. A vacuum-electronic microwave source is a kind of slow-wave FEL, which has been extensively studied in the past few decades. The radiation wavelength of the slow-wave FEL is comparable to the smallest feature size of the slow-wave structure. With the advancement of micro-fabrications, a slow-wave FEL is promising in generating coherent radiations in the UV, visible, and THz regimes. In the talk, I will present our research on the development of keV electron injectors with novel photocathodes aiming to drive various photonic structures to generate coherent radiations. This work is supported by the National Science and Technology Council under Contract NSTC 112-2112-M-007 -028 -MY3.

Keywords: free-electron laser, vacuum electronics, photonic structure