New Horizons of Near-field Optical Microscopy

Structure, functions, dynamics, and interactions are the basic properties to systematically understand physical systems existing in nature. In particular, there have been many scientific adventures to understand optical properties of materials and light-matter interactions, yet in the classical regime at the microscale due to the diffraction-limited optical resolution. Near-field optical microscopy enables to probe them at the nanoscale and even induces light-matter interactions in a reversible fashion. In this article, we introduce the fundamental concept of various types of near-field microscopy and several applications studies reported recently. Furthermore, we provide several new directions of nano-spectroscopy and -imaging based on tip-enhanced approach, which have not been thought in the near-field optics community before.