Life Beyond Diffraction: Opening New Routes to Materials Characterization with Next‐Generation Optical Near‐Field Approaches

Near‐field optical microscopies and spectroscopies seek to investigate materials by combining the best aspects of optical characterization and scan‐probe microscopy techniques. In principle, this provides access to chemical, morphological, physical and dynamical information at nanometer length scales that is impossible to access by other means. But a number of challenges, particularly on the scan‐probe front, have limited the widespread application of near‐field investigations. This work describes how recent probe engineering and technique innovation have addressed many of these challenges. This Feature Article begins with a short overview of the field, providing perspective and motivation for these developments and highlighting some key improvements. This is followed by a more in‐depth description of the near‐field advances developed at the Molecular Foundry, a national nanoscience User Facility–advances that provide groundwork for generally‐applicable nano‐optical studies. Finally, a discussion is provided of what progress is still needed in order to realize the ultimate objective of translating all optical measurements to the nanoscale.