Lara Wimmer | Searcharxiv

arXiv2020

Phase space manipulation of free-electron pulses from metal nanotips using combined THz near-fields and external biasing

We present a comprehensive experimental and numerical study of photoelectron streaking at metallic nanotips using single-cycle Terahertz (THz) transients and a static bias voltage as an external control parameter. Analyzing bias voltage dependent streaking spectrograms, we explore the THz-induced reshaping of photoelectron energy spectra, governed by the superimposed static field. Numerical simulations are employed to determine the local field strengths and spatial decay lengths of the field contributions, demonstrating electron trajectory control and the manipulation of the phase space distributions in confined fields with both dynamic and static components.

physics.optics↗

arXiv2020

Clocking plasmon nanofocusing by THz near-field streaking

We apply terahertz (THz) near-field streaking in a nanofocusing geometry to investigate plasmon polariton propagation on the shaft of a conical nanotip. By evaluating the delay between a streaking spectrogram for plasmon-induced photoemission with a measurement for direct apex excitation, we obtain an average plasmon group velocity, which is in agreement with numerical simulations. Combining plasmon-induced photoemission with THz near-field streaking facilitates extensive control over localized photoelectron sources for time-resolved imaging and diffraction.

physics.optics↗