Berlin 2018 – scientific programme

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O: Fachverband Oberflächenphysik

O 77: Poster: Plasmonics and Nanooptics

O 77.14: Poster

Wednesday, March 14, 2018, 18:15–20:30, Poster A

Density matrix formalism in ultrafast electron microscopy — •Sergey V. Yalunin, Katharina E. Priebe, and Claus Ropers — University of Göttingen, 4th Physical Institute, Göttingen 37077, Germany

Electron-photon interactions are currently a subject of high interest in ultrafast electron imaging and microscopy [1]. Beyond the use in optical near-field imaging, such interactions may be important for the observation of quantum entanglement dynamics in solids, in the context of pump-probe experiments, using the free single-electron state as a quantum probe. However, this requires both a proper theoretical description of the underlying quantum processes and a quantum reconstruction algorithm of the electron state. Due to the limited number of projective measurements, the quantum reconstruction becomes essentially ill-posed in the sense that the matrix transformation describing the measurement does not have a bounded inverse. To demonstrate the feasibility of quantum reconstruction, we consider a situation where electrons initially prepared in a pure quantum state interact with two partially coherent laser pulses focused on a nanostructure. We reconstruct the final mixed quantum state of the electron ensemble and the properties of the laser field, contrasting the results with recent data [2] obtained with the Göttingen Ultrafast Transmission Electron Microscope (UTEM).

[1] B. Barwick, and A. H. Zewail, Nature 462, 902-906 (2009).

[2] K. E. Priebe et al., Nature Photonics 11, 793-797 (2017).