Speaker
Description
Ultrafast electron microscopy is an emerging field with a rapidly growing number of labs, and with it comes a need for robust, well-engineered platforms that can support increasingly complex experiments. We present a dedicated ultrafast scanning electron microscope built to bring quantum science to the SEM, now offered through the recently formed company QSEM. QSEM was founded by Claus Ropers, Murat Sivis, and John Gaida together with CEOS GmbH and the Max Planck Society, uniting expertise in ultrafast electron microscopy, electron optics, and precision instrumentation into a single multimodal platform. Ultrafast electron microscopy enables femtosecond-scale access to out-of-equilibrium structural and electronic processes at the nanoscale. QSEM makes these capabilities more accessible by bringing them to the SEM architecture, including transmission detection.
The instrument employs femtosecond pulsed linear photoemission from a Schottky field emitter and offers simultaneous transmission, reflection, and secondary-electron detection from 100 eV to 30 keV. It is UHV-capable and highly extensible, integrating an energy filter for electron spectroscopy developed jointly with CEOS, a transfer lens for flexible camera lengths and differential pumping enabling the use of non-UHV detectors, a high-NA parabolic mirror for optical access, and a flexible scan generator for user-defined acquisition schemes. Together, these elements support energy-filtered nanobeam diffraction, 4D-STEM, electron spectroscopy, cathodoluminescence, and correlated electron–light detection.
In collaboration with the Department of Ultrafast Dynamics led by Claus Ropers at the Max Planck Institute for Multidisciplinary Sciences, raster-scanned nanobeam diffraction has resolved nanoscale structural heterogeneity in the layered quantum material 1T-TaSe₂, demonstrating the platform's reach into structural, electronic, and quantum-optical phenomena. As the QSEM user community grows, we envision the platform evolving into a shared foundation for ultrafast and quantum-optical experiments, with new detection schemes and capabilities developed jointly across labs.