Spatial compression and deflection of free electrons by electron-plasmon field interactions

Abstract The modulation of electron beams is a critical area for investigating the interaction between electrons and matter. By harnessing the inelastic scattering process of free electrons and surface plasmon polaritons (SPPs), we can effectively manipulate the electron beam. Our study shows that electron beams can be compressed and deflected through electron-plasmon field interaction, which adds to the existing research on spatial control of electron beams. Specifically, considering the interaction between an electron beam and counterpropagating SPPs with two wave-vectors, asymmetric diffraction and transverse compression of coherent Gaussian electron beams are predicted employing semi-classical theory. This effect can be understood by analyzing the symmetry breaking and exchange properties between momentum and position in the Fourier plane. Our findings demonstrate a linear superposition of transverse momentum associated with electron and structural plasmon fields, offering the potential for active modulation to program transverse electron wave functions and presenting alternative solutions for accelerator science.