New paper on a novel THz-driven accelerating structure
A new study led by EuPRAXIA-DN Fellow Andrés Leiva Genre at the University of Pécs proposes a novel accelerating structure that combines two previously separate technologies, a tapered parallel-plate waveguide (TPPWG) and a dielectric terahertz-driven accelerator (DTA), into a single compact device. The work, carried out with colleagues at the University of Pécs and the HUN-REN—PTE High-field Terahertz Research Group, is published in Optics and Laser Technology under the title "A novel accelerating structure based on a tapered parallel-plate waveguide with an integrated dielectric terahertz-driven accelerator."
The article explores accelerating relativistic electrons using a tapered parallel-plate waveguide integrated with a dielectric terahertz-driven accelerator. Although both devices have already been studied individually, they had never been combined into a single structure for particle acceleration and beam manipulation. The waveguide couples incoming terahertz pulses into a confined geometry and amplifies the local electric field through geometric tapering, delivering an enhanced field to a dual-pillar dielectric grating that transfers energy to the electron bunch.
The team validated the terahertz field propagation and amplification inside the waveguide experimentally, using electro-optic sampling, and found close agreement with simulations, confirming a sixfold peak electric field amplification at the end of the waveguide. Building on this validated waveform, particle-in-cell simulations of the full structure showed that it can support net electron acceleration with gradients of up to 1.2 MeV/cm at 1 MV/cm field strengths, while accommodating bunch charges of up to 10 pC with minimal degradation.
According to simulations, the proposed structure can reach acceleration gradients of 120 MeV/m when accelerating a 10 pC electron bunch using current technology. Because the design can be adapted to sub-relativistic beams as well as ultra-relativistic ones, it could be operated not only for acceleration but also for other beam manipulation techniques such as deflection, streaking, and bunching.
The result is a compact and scalable platform for high-gradient THz-driven acceleration that combines a simple, easily fabricated design with strong field enhancement and compatibility with existing electron sources, opening new pathways toward practical, tabletop accelerators for scientific and industrial applications.
Further information:
Leiva Genre, A., Tibai, Z., Nasi, L., Kiss, M., Almási, G., Hebling, J., Turnár, S. "A novel accelerating structure based on a tapered parallel-plate waveguide with an integrated dielectric terahertz-driven accelerator", Optics and Laser Technology, 204, 116050 (2026). https://doi.org/10.1016/j.optlastec.2026.116050
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