Femtosecond single- to few-electron point-projection microscopy for nanoscale dynamic imaging

Abstract

Femtosecond electron microscopy produces real-space images of matter in a series of ultrafast snapshots. Pulses of electrons self-disperse under space-charge broadening, so without compression, the ideal operation mode is a single electron per pulse. Here, we demonstrate for the first time femtosecond single-electron point projection microscopy (fs-ePPM) in a laser-pump fs-e-probe configuration. The electrons have an energy of only 150 eV and take tens of picoseconds to propagate to the object under study. Nonetheless, we achieve a temporal resolution with a standard deviation of 120 fs, combined with a spatial resolution of 100 nm, applied to a localized region of charge at the apex of a nanoscale metal tip induced by 30 fs 800 nm laser pulses at 50 kHz. These observations demonstrate real-space imaging of reversible processes such as tracking charge distributions is feasible whilst maintaining femtosecond resolution. Our findings could find application as a characterization method, which, depending on geometry could resolve tens of femtoseconds and tens of nanometres. Dynamically imaging electric and magnetic fields and charge distributions on sub-micron length scales opens new avenues of ultrafast dynamics. Furthermore, through the use of active compression, such pulses are an ideal seed for few-femtosecond to attosecond imaging applications which will access sub-optical cycle processes in nanoplasmonics.

14 pages, 8 figures, submitted to Structural Dynamics

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Cited by in corpus (7)

• Ultrafast transmission electron microscopy using a laser-driven field emitter: femtosecond resolution with a high coherence electron beam
• A nanofocused plasmon-driven sub-10 femtosecond electron point source
• Schroedinger electrons interacting with optical gratings: quantum mechanical study of the inverse Smith Purcell effect
• Ultrafast Relativistic Electron Nanoprobes
• High spatial coherence in multiphoton-photoemitted electron beams
• Strong inelastic scattering of slow electrons by optical near fields of small nanoparticles
• Ultrafast Electron Diffraction: Visualizing Dynamic States of Matter