867. Wilhelm and Else Heraeus Seminar on "Quantum Electron-Photon Interactions"

From Free-Electron Bound-Electron Resonant Interactions to Sensing of Microwave-Driven Spin Precession with Free Electrons

Not scheduled

20m

Charles University (Prague)

Invited talk

Speaker

Philipp Haslinger (TU Wien)

Description

Coherent control and detection of quantum systems are central to quantum technologies. Beyond excitation with optical and microwave fields, free-space electrons can be used to manipulate and detect quantum systems with unique spatial and spectroscopic resolution. In this talk, I outline the theoretical framework [1, 2] showing that the non-radiative near-field of a spatially modulated electron beam can coherently drive quantum systems and show preliminary experimental data [3]. I then present our SPINEM (Spin Electron Microscopy) platform [4], which integrates continuous-wave electron spin resonance (ESR) spectroscopy into a transmission electron microscope (TEM). Using a miniaturized microwave resonator with the free-space electrons of a TEM [5], we enable in-situ, phase-locked detection of microwave-driven spin precession with picoradian deflection sensitivity (<300 prad) for localized spin spectroscopy. Finally, I discuss a roadmap toward magnetic resonance imaging (MRI) with aloof electrons, enabling magnetic resonance studies with reduced radiation damage. I will present estimates indicating a path toward atomic spatial resolution and single-spin sensitivity [6], opening new opportunities in nanoscale spintronics, magnonics, quantum materials, and quantum technologies.
[1] A. Gover, A. Yariv, Free-electron–bound-electron resonant interaction, Phys. Rev. Lett. 124, 064801, (2020)
[2] D. Rätzel, D. Hartley, O. Schwartz, and P. Haslinger, Controlling Quantum Systems with Modulated Electron Beams, Phys. Rev. Res. 3, 023247, (2021)
[3] M. Kolb, T. Spielauer, T. Weigner, G. Boero, D. Rätzel, P. Haslinger, Coherent Driving of a Quantum System with Modulated Free-Space Electrons, arXiv:2509.13904 (2025)
[4] A. Jaroš, J. Toyfl, A. Pupić, B. Czasch, G. Boero, I. Bicket, P. Haslinger Electron spin resonance spectroscopy in a transmission electron microscope, Ultramicroscopy, 278, 114224, (2025)
[5] A. Jaroš, M. Seifner, J. Toyfl, B. Czasch, S. Beltrán-Romero, I. Bicket, P. Haslinger, Sensing Spin Precession with Free Electrons, ACS Nano, 20, 4, 3435, (2026)
[6] P. Haslinger, S. Nimmrichter, D. Rätzel, Spin Resonance Spectroscopy With an Electron Microscope, QST, 9, 035051 (2024)