Speaker
Description
Recent advances in Transmission Electron Microscopy (TEM), including aberration correction, cryogenic stabilization, and ultrafast electron pulses, have pushed spatial and temporal resolution to unprecedented levels. Yet extending this precision to the detection of single spins of the investigated samples and their magnetic dynamics remains a major challenge. Here, we present a theoretical and computational framework for Spin Resonance Spectroscopy, e.g. nuclear (NMR) or electron spins (ESR) in TEM, enabling nanoscale, state-selective spin imaging through the coherent interaction of electron probes with microwave-driven spin systems.
Our model explicitly describes the coupling between free electrons and localized spins, capturing the resulting phase shifts and deflection angles in the electron wave function. Implemented within a pump–probe spin resonance scheme, it combines scattering theory with quantum metrology to determine precision limits and optimal detection strategies for both single-spin and ensemble measurements. Sensitivity is quantified via the Classical Fisher Information and compared against the Quantum Fisher Information and Helstrom bound.
We find that diffraction and imaging measurements can approach quantum-limited performance when electron backaction is negligible, corresponding to classical magnetic dipoles. In contrast, when backaction from a quantum spin becomes significant, orbital angular momentum-resolved detection restores access to quantum-limited sensitivity. Our results establish the quantum bounds of spin sensing using free-space electrons as probe particles and provide guidance for future experiments targeting spin detection and magnetic imaging, uniting the spectral selectivity of NMR and ESR with the spatial resolution of electron microscopy.
References
[1] Antonín Jaroš, Johann Toyfl, Andrea Pupić Benjamin Czasch, Giovanni Boero, Isobel C. Bicket, and Philipp Haslinger, Electron spin resonance spectroscopy in a transmission electron microscope, Ultramicroscopy 278 (2025) 114224, arXiv:2408.16492.
[2] Antonín Jaroš, Michael S. Seifner, Johann Toyfl, Benjamin Czasch, Isobel C. Bicket, and Philipp Haslinger, Sensing spin systems with a transmission electron microscope, arXiv:2503.06761.
[3] P. Haslinger, S. Nimmrichter, and D. Rätzel, Spin resonance spectroscopy with an electron microscope, Quantum Science and Technology 9, 035051 (2024).
[4] S. Beltran-Romero, S. Löffler, D. Rätzel, and P. Haslinger, Simulating Quantum Spin Imaging in Transmission Electron Microscopy for Pump-Probe Spin Resonance Spectroscopy, Manuscript in development
[5] S. Beltran-Romero, M. Gaida, S. Nimmrichter, D. Rätzel, and P. Haslinger, Quantum Metrology of Spin Sensing with Free Space Electrons, arXiv:2509.14982
