Prof. Dr. Nahid Talebi
Institute for Experimental and Applied Physics, Kiel University, Kiel, Germany:
Phased-Locked Photon-Electron Spectroscopy
Mechanisms of radiation from electron beams are routinely tailored in gigantic infrastructures such as free-electron lasers to perform coherent spectroscopy of materials excitations. However, even nano and mesoscale structures could provide sufficient tailoring mechanisms in interaction with electrons, to be applied to spectroscopy techniques [1-4]. Here, we provide the first proof-of-concept experiment highlighting the coherent mechanisms involved in phase-locked photon-electron spectroscopy of quantum materials and their dynamics. In our approach, precisely engineered electron-driven photon sources (EDPHSs) are used as photon clocks. The radiation from the EDPHS excites the sample at a delay (Tau) with respect to the electron beam, that is controlled by changing the distance between the sample and the EDPHS. In addition, this technique allows us to directly map the decoherence mechanism by investigating the visibility of the spatial and spectral interference fringes. Using WSe2 thin films as samples, we will specify the formation of exciton polaritons due to the self-hybridization effect and the associated spatial coherence as captured by electron-beam spectroscopy [5, 6]. Phased-locked photon-electron spectroscopy when applied to WSe2 flakes, allows us to unravel the photon-mediated spectral correlations between A and B excitons.

References

1. N. van Nielen, M. Hentschel, N. Schilder, H. Giessen, A. Polman, N. Talebi, Nano Lett.20 (8), 5975-5981 (2020)
2. N. Talebi, S. Meuret, S. Guo, M. Hentschel, A. Polman, H. Giessen, P. van Aken, Nat. commun.10 (1), 1-8 (2019)
3. J. Christopher, M. Taleb, A. Maity, M. Hentschel, H. Giessen, N. Talebi Nanophotonics 9 (15), 4381-4406 (2020)
4. N. Talebi, Phys. Rev. Lett.125, (2020) 080401
5. M. Taleb, F. Davoodi, F. Diekmann, K. Rossnagel, N. Talebi, Advanced Photonics Research2100124, 1 (2021)
6. F. Chahshouri, M. Taleb, F. K. Diekmann, K. Rossnagel, N. Talebi, J. Phys. D: Appl. Phys.55 (14), 145101 (2022)