Branden L. Esses, Daniel Sandner, Patrick A. McKee, Roland Wilcken, Jun Nishida, Richard Puro, Markus B. Raschke
Ultrafast near-field microscopy unites femtosecond optical spectroscopy with nanometre spatial resolution to image non-equilibrium material dynamics beyond the diffraction limit. This Primer outlines theory, instrumentation, signal interpretation and representative applications, providing a practical foundation for generating and analysing ultrafast nano-movies of quantum materials.