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O: Fachverband Oberflächenphysik
O 18: Poster Focus Session Ultrafast Electron Microscopy at the Space-Time Limit
O 18.6: Poster
Montag, 17. März 2025, 18:00–20:00, P2
Monochromatization of Electron Beams with Spatially and Temporally Modulated Optical Fields — •Neli Laštovičková Streshkova1, Petr Koutenský1, Tomáš Novotný2, and Martin Kozák1 — 1Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, CZ-121 16 Prague, Czech Republic — 2Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, Prague CZ-12116, Czech Republic
Inelastic interaction between coherent light and free electrons is a powerful tool for modulating electron wave packets, typically resulting in periodic sidebands in the electron energy spectra. We present a novel approach leveraging a time-dependent frequency modulation of light fields to achieve spectral squeezing and monochromatization of free electron pulses. This method compensates for the energy chirp inherent to dispersive propagation in electron sources like TEMs and SEMs, where finite coherence lengths lead to broadened energy spectra. By correcting the chirped wave packet in the energy-time domain through inelastic interaction with tailored optical fields, we enable significant spectral narrowing. Up to 26% of the electron distribution is concentrated within a narrowed energy band, achieving spectral compression by a factor of five. This advancement has implications for high-resolution quantum sensing and electron-based spectroscopy, addressing a critical need for low-loss electron monochromatization.
Keywords: electron beam monochromatization; quantum coherent control; chirped optical pulses; ponderomotive scattering; electron beam shaping