Raster scan imaging in atomic force microscopy: New perspectives and potential of using signal and system theory

Recent advances in high-performance Atomic Force Microscopy (AFM) allow real-time, atomic-scale imaging, but often require expensive equipment. This work revisits the AFM imaging technique and proposes a novel software-based solution for conventional AFMs operated in tapping mode to achieve both high-speed scans and high-resolution images using existing hardware. By treating an AFM scan as a signal modulation process, this method retrieves AFM images directly from signal demodulation. The method captures and analyzes the AFM probe's feedback signal, decomposing it into low- and high-frequency components. The low-frequency signal, representing raster scan motion, undergoes segmentation. The high-frequency signal, containing image information, is demodulated and segmented. These steps generate two sets of signals used to build the final AFM images. Validated on a standard AFM with extensive experiments at scanning speeds up to 240 μm/s, this flexible and easy-to-implementation method unlocks the potential for high-performance, affordable AFM in materials science research.