Dresden 2017 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 63: Poster: Quantum Dots and Optics

HL 63.12: Poster

Mittwoch, 22. März 2017, 15:00–19:00, P1A

Source Development for Ultrafast Transmission Electron Microscopy — •Nora Bach, Armin Feist, Katharina E. Priebe, Nara Rubiano da Silva, Thomas Danz, Marcel Möller, Jan Gregor Gatzmann, Stefan Rost, Jakob Schauss, Stefanie Strauch, Reiner Bormann, Murat Sivis, Sascha Schäfer, and Claus Ropers — 4th Physical Institute - Solids and Nanostructures, University of Göttingen, Germany

Ultrafast transmission electron microscopy (UTEM) is a novel experimental technique that combines nanoscale spatial with femtosecond temporal resolution [1]. However, the achievable performance for imaging and diffraction is limited by the brightness of current laser-driven electron sources.

Here, we present the design and implementation of an advanced UTEM instrument based on the modification of a commercial Schottky field emission TEM [2,3]. Single-photon photoemission from a tip-shaped ZrO/W(100) emitter is employed, yielding electron pulses with a spectral bandwidth of 0.6 eV, a low beam emittance of about 1-10nm mrad, and an electron probe size down to 0.9 nm. We characterize the temporal structure of the electron pulses by electron-photon cross-correlation and obtain pulse widths down to 200 fs (full-width-at-half-maximum). The high beam quality demonstrated will enable new applications in the study of nanoscale ultrafast dynamics, including ultrafast electron holography and phase-contrast imaging.

[1] A. H. Zewail, Science 328, 187 (2010) [2] A. Feist et al., Nature 521, 200 (2015) [3] A. Feist et al., arXiv:1611.05022 (2016)