Biography:

Nahid Talebi graduated from Tehran University with a PhD in Electrical Engineering in 2011, defended with distinction. During her studies, she visited the Max Planck Institute in Stuttgart for the duration of 7 months with a Scholarship from the Max Planck Society. In 2012, she joined the Stuttgart Center for Electron Microscopy as an Alexander von Humboldt Research Fellow. In 2015, she became a group leader at the Max Planck Institute for Solid State Research and in 2018, she received an ERC Starting Grant from the European Research Council. In 2019, she joined the Christian Albrechts University in Kiel as an associate professor and a director of the Institute for Experimental and Applied Physics, holding the chair for Nanooptics. Her work concerns exploring the interaction of electron beams with light and nanostructures, to both investigate fundamental quantum mechanical aspects of electron-light interaction and to propose and realize novel characterization techniques with electron beams. She has expertise in computational physics, particularly numerical electrodynamics and Maxwell-Schrödinger formalism and drafted more than 60 papers in high-impact journals and a monograph book in Springer (“Near-Field-Mediated Photon–Electron Interactions,” Springer Series in Optical Sciences, Berlin (2019)). She is the editor of Optica, has organized a number of international symposium and conferences worldwide, and also were invited to more than 40 colloquiums, conferences, and workshops as plenary and invited speakers.

LECTURE: "Electron-Light Interactions Simulated with Multiscale Maxwell-Schrödinger Framework"

The investigation of material excitations dynamics using electron microscopes has become feasible through the integration of light and electron sources in a unified microscopy/spectroscopy platform. This platform allows us to explore the optical density of states of nanostructures, among other applications. In this study, we focus on the interactions between light and free-electron wavepackets, employing a simulation toolbox that combines Maxwell's and Schrödinger's equations.

When considering electron-light interactions in free-space, these interactions can be either elastic or inelastic. The generalization of the Kapitza-Dirac effect to inelastic scattering can be achieved by incorporating various light beams of different colors or structured light [3]. In the case of near-field light, both elastic and inelastic contributions are observed [4], enabling us to determine the strength of electron-light interactions through diffraction and spectroscopy. We also discuss future prospects for extending the numerical techniques to include the interaction of preshaped electron beams with light and quantum matter.

References:
[1] N. Talebi, Phys. Rev. Lett. 125, 080401 (2020).
[2] N. Talebi, Advances in Physics: X 3 (1), 1499438 (2018)
[3] S. Ebel and N. Talebi, arXiv:2212.10255 (2023)
[4] N. Talebi, Near-Field-Mediated Electron-Photon Interactions, Springer Series in Optical Sciences (2019)

TALK: "Phase-Locked Photon-Electron Interactions in Electron Microscopes"

Quasiparticle dynamics in two-dimensional materials occur on an ultrafast timescale ranging from femtoseconds to picoseconds. In this study, we investigate the strong interaction between excitons and photons in thin films of transition metal dichalcogenides, which give rise to propagating exciton polaritons through self-hybridization effects. Additionally, we showcase how cathodoluminescence spectroscopy can be employed to map the extremely short propagation length of self-hybridized exciton polaritons (1). Furthermore, we explore the intricate interplay between excitons, photons, and plasmons, resulting in the formation of complex composites with fascinating characteristics, including the emergence of flat optical bands.
We also present a novel approach to ultrafast photon-electron spectroscopy techniques within electron microscopes (2). Our method involves utilizing cathodoluminescence
spectroscopy, where an electron beam sequentially interacts with an electron-driven photon source (3-5) and the sample. By configuring this setup, we achieve phase-locked photons that
exhibit mutual coherence with the near-field distribution of the fast-moving electrons. Through our experimental findings, we demonstrate the frequency and momentum-dependent correlation between the electron-driven photon source and the radiation from the sample.
This remarkable level of mutual coherence allows us to perform spectral interferometry using an electron microscope.

References:
1. Taleb, M.; Davoodi, F.; Diekmann, F. K.; Rossnagel, K.; Talebi, N., Charting the Exciton–Polariton Landscape of WSe2 Thin Flakes by Cathodoluminescence Spectroscopy. Advanced Photonics Research 2022, 3 (1), 2100124.
2. Chahshouri, F.; Talebi, N., Tailoring near-field-mediated photon electron interactions with light polarization. New Journal of Physics 2023, 25 (1), 013033.
3. Talebi, N.; Meuret, S.; Guo, S.; Hentschel, M.; Polman, A.; Giessen, H.; van Aken, P. A., Merging transformation optics with electron-driven photon sources. Nature Communications 2019, 10 (1), 599.
4. van Nielen, N.; Hentschel, M.; Schilder, N.; Giessen, H.; Polman, A.; Talebi, N., Electrons Generate Self-Complementary Broadband Vortex Light Beams Using Chiral Photon Sieves. Nano Letters 2020, 20 (8), 5975-5981.
5. Christopher, J.; Taleb, M.; Maity, A.; Hentschel, M.; Giessen, H.; Talebi, N., Electron-driven photon sources for correlative electron-photon spectroscopy with electron microscopes. Nanophotonics 2020, 9 (15), 4381-4406.