THz-driven electron manipulation via non-velocity-matched interaction in dielectric-loaded waveguides

Multi-cycle THz-driven electron compression and focusing in dielectric-loaded waveguides (DLWs) offer a compact solution for precise ultrafast electron beam control. However, practical implementation often suffers from dephasing effects due to fabrication tolerances. Here, we investigate the dynamics of electron beam control in the non-velocity-matched interactions between electron beams and THz waves within the DLWs, revealing the relationship between velocity mismatch and the THz energy required for effective electron manipulation. Moreover, we propose a method for achieving cascaded electron compression and focusing within a single DLW by matching the electron beam to different phase components of the THz wave. This adaptable strategy could significantly broaden the applications of THz-driven devices in generating high-quality ultrafast electron sources.