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Femtosecond Lorentz Microscopy for the Mapping of Ultrafast Magnetization Dynamics

Time-resolved and in-situ electron microscopy techniques offer a unique access to dynamical processes at the nanoscale. Pushing the limits of temporal resolution, ultrafast transmission electron microscopy (UTEM) [1, 2] utilizes ultrashort electron pulses to stroboscopically map transient states of matter. Recent advances in nanoscale photocathode technology allowed for the generation of high-coherence electron pulses with a temporal duration down to 200 fs, focusable to sub-nanometer spot-sizes and with a narrow spectral width of 0.6 eV [2, 3]. High quality electron pulses now open the possibility to equip a broad range of electron microscopy techniques with femtosecond temporal resolution, including bright-field imaging [4], electron-energy spectroscopy [5] or convergent-beam electron diffraction [6].