Erlangen 2022 – scientific programme

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SYQC: Symposium Quantum Cooperativity of Light and Matter

SYQC 1: Quantum Cooperativity of Light and Matter - Session 1

SYQC 1.5: Talk

Thursday, March 17, 2022, 11:45–12:00, Audimax

Coulomb interactions in pulsed laser-triggered electron beams from tungsten needle tips — •Stefan Meier, Jonas Heimerl, and Peter Hommelhoff — Department Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91058 Erlangen

Tungsten needle tips represent well-suited electron sources for various applications, including electron diffraction, electron microscopy or electron holography. In cold field emission, these tips provide a highly coherent electron beam, with coherence being the key parameter for most electron-optical applications. When femtosecond laser pulses are focused on the tip, electrons can be emitted promptly, leading to an ultrafast pulsed electron source. Previously, we could show that femtosecond pulsed electron emission is spatially as coherent as cold field emission from the same tip when operated with currents well below one electron per pulse on average [1]. In this talk, we show that the spatial coherence decreases when more than one electron per pulse is emitted on average, starting already at below one electron per pulse. These results are quantitatively well supported by numerical point-particle simulation results. Last, we show that the coherence decrease can be interpreted as an effective source size growth [2]. We will conclude with an outlook on the current status of correlation measurements, which might allow us to enter the quantum correlation regime and might, ultimately, yield quantum limited electron beams.
[1] S. Meier et al., Appl. Phys. Lett. 113, 143101 (2018).
[2] S. Meier and P. Hommelhoff, manuscript submitted.