Recently, the State Key Laboratory of Intense Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, has made new progress in the field of terahertz driven waveguide acceleration. This study proposes a cascaded acceleration scheme based on hollow metal tubes, confirming the feasibility of a desktop 100 MeV level high-energy electron accelerator. The relevant research results are titled "Hollow metal tubes for effective electron manipulation using terahertz surface waves" and published in Optics Express.

A miniaturized electron accelerator will drive its application in cutting-edge science and technology fields. The use of terahertz wave driven electron acceleration, as an emerging acceleration technology developed in the past decade, can provide a higher acceleration gradient than traditional RF acceleration, and is one of the reliable ways to achieve miniaturization and low-cost acceleration devices. It is expected to promote the application of accelerators to more application scenarios, including small laboratories, hospitals, etc.

On the basis of verifying the first terahertz waveguide electron acceleration with energy gain up to MeV internationally, this study uses a high-quality external injection electron source to achieve more flexible acceleration and compression mode control of the electron beam. Under the action of a 2.9 mJ THz pulse, the tunable electron energy reached ± 860 keV and demonstrated enhanced compression from 400 fs to less than 70 fs. At the same time, in order to further improve energy and achieve a "desktop" high-energy electron accelerator, a waveguide cascade scheme using an externally injected electron source has been proposed, confirming the feasibility of a desktop 100 MeV level high-energy electron accelerator. It can reduce the size of traditional accelerators from kilometer level to meter level, and is expected to pave the way for compact and efficient terahertz driven electron sources.

The research work was supported by the National Natural Science Foundation of China and the Chinese Academy of Sciences.

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Schematic diagram of external injection electronic source scheme



Terahertz waveguide cascade acceleration scheme