Off the grid: Advanced scanning strategies for modern STEM
Conventional scanning transmission electron microscopy (STEM) experiments are performed with a raster scan approach, where the electron beam is scanned in a regular rectangular pattern. This design minimizes the distance the probe needs to traverse along the fast scan direction, but it may not be the optimal approach for many samples and inherently introduces artifacts due to the asymmetry in fast and slow scan directions. Recent studies have suggested how advanced scan patterning with non-raster trajectories, including spiral patterns and multipass scans, can modify the impact of beam-specimen interactions, reducing sample damage. Advanced scanning can also be used to drive specific beam-specimen interactions, including nano- to atomic- scale patterning of samples. These advanced scanning approaches can be combined with other low-dose strategies, including phase retrieval techniques, such as differential phase contrast, parallax, and ptychography.
In this webinar, we will introduce these methods and show our results using the Gatan Digiscan 3 platform to encode a variety of scan patterns for electron energy loss spectroscopy (EELS) and 4D STEM experiments. Specifically, we will highlight how these approaches are compatible with atomic-resolution imaging, cryo-electron microscopy, and state-of-the-art techniques, including iterative electron ptychography. In addition, in-situ control of electron-beam scan patterns enables domain motion to be driven and topological states to be written in a controlled and programmable manner.
Palos, Mariana, et al. "Programmable Beam Control for Electron Energy-Loss Spectroscopy and Ptychography." arXiv preprint arXiv:2509.10726 (2025). https://arxiv.org/abs/2509.10726