Terahertz acceleration

AXSIS [1] and the Accelerator on a chip (ACHIP) projects in the UFOX group are aiming to miniaturize electron accelerators in order to open up new realms of applications of electron sources. Terahertz (THz) accelerators are based on the same concepts as conventional, radio-frequency accelerators, but use high-field pulses of THz radiation generated by nonlinear down-conversion of lasers to enable intensely strong manipulation of electrons [2,3,4].

As these devices are fully optically driven and can fit in the palm of your hand, they are ideal for integration into table-top optical setups, bringing the versatility of the world of photonics to the realm of electrons. Using radiation with wavelengths in the range of 1 mm and electric field strengths of order 1 GV/m, we have established records in THz acceleration, compression, focusing and streaking of electrons [5] which prove the feasibility of this approach.

 

This work is being done in partnership with UFOX's Solid state lasers team to develop new laser technologies and achieve new records in generation of THz radiation [6]. The goal is to use THz accelerators to construct compact, high-brightness femtosecond and attosecond sources of MeV electrons and keV X-rays.

These sources will provide capabilities for probing material structure on atomic spatial and temporal scales which will complement attosecond EUV sources developed by the Optical parametric synthesizer and Attosecond science teams at UFOX in the mission to decode nature's processes like photosynthesis.

Relevant references:
[1] F. X. Kärtner, et al., AXSIS: Exploring the frontiers in attosecond X-ray science, imaging and spectroscopy Nucl. Instr. Meth. Phys. Res. A 829, 24-29 (2016).
[2] E. A. Nanni et al., Terahertz-driven linear electron acceleration Nature Comm. 6, 8486 (2015).
[3] A. Fallahi et al., Short electron bunch generation using single-cycle ultrafast electron guns Phys. Rev. Accel. Beams 19, 081302 (2016).
[4] W. R. Huang et al., Terahertz-driven, all-optical electron gun Optica 11, 1209 (2016).
[5] D. Zhang, et al., Segmented Terahertz Electron Accelerator and Manipulator (STEAM), Nat. Photonics 12, 336-342 (2018).
[6] S. W. Jolly et al., Spectral phase control of interfering chirped pulses for high-energy narrowband terahertz generation Nature Comm. 10, 2591 (2019).