Advances and challenges in dynamic photo-induced force microscopy

Photo-induced force microscopy (PiFM) represents a scanning probe technique renowned for its ability to provide high-resolution spectroscopic imaging at the nanoscale. It capitalizes on the amplification of tip motion by photo-induced forces, which are influenced by the response of the local medium, spanning from induced dipole interactions to thermal expansion. The behaviors of these force responses exhibit complexity in connection with both far-field and near-field effects, depending on their spectroscopic origins. In this review, we aim to provide a comprehensive overview of prior research endeavors, shedding light on their technical intricacies. We provide the perspectives of photo-induced dipole force and photo-induced thermal force, while exploring the dynamic PiFM modes associated with each scenario. Our article targets individuals newly venturing into this field, offering a blend of theoretical foundations and practical demonstrations covering a range from fundamental principles to advanced topics.