Nanomaterials have attracted significant attention in recent years for various fascinating applications, including ultrasensitive chemical/biological sensors, recording media, electronic circuits, nano-medical treatments, and so forth. Spectroscopy at high spatial and time resolutions is needed to attain direct access to the fundamental nature of nanomaterials. The spatial resolution of conventional optical microscopes is diffraction-limited to approximately several hundreds of nm. Near-field optical methods overcome the diffraction limit of light and achieve nanometric spatial resolution. The advantages of the near-field method go beyond high spatial resolution and include potential compatibility with various advanced spectroscopic techniques, such as time-resolved and nonlinear methods developed in the field of laser spectroscopy. The near-field methods enable us to obtain spectroscopic information of nanomaterials in a real space.
The research interests currently focus on the properties of surface plasmon resonances excited in noble metal nanostructures and their significance for chemical reactions. Plasmons confine optical fields in the vicinity of nanomaterials and enhance optical fields locally. This enhancement is of several orders of magnitude, opening up not just new research fields, but various potential applications. For basic research, since the spatial scale of the optical field becomes comparable to that of the materials, we expect strong, anomalous light-matter interactions beyond the dipole approximation. On the other hand, in applications, for instance, the optical field can be utilized for sensing purposes, since the enhanced field significantly amplifies Raman scattering from molecules to achieve detection sensitivity capable of detecting even single molecules. Imaging the plasmon wave function is essential for designing and controlling the properties of plasmon-based materials and for finding applications to basic research.
The research interests currently focus on the properties of surface plasmon resonances excited in noble metal nanostructures and their significance for chemical reactions. Plasmons confine optical fields in the vicinity of nanomaterials and enhance optical fields locally. This enhancement is of several orders of magnitude, opening up not just new research fields, but various potential applications. For basic research, since the spatial scale of the optical field becomes comparable to that of the materials, we expect strong, anomalous light-matter interactions beyond the dipole approximation. On the other hand, in applications, for instance, the optical field can be utilized for sensing purposes, since the enhanced field significantly amplifies Raman scattering from molecules to achieve detection sensitivity capable of detecting even single molecules. Imaging the plasmon wave function is essential for designing and controlling the properties of plasmon-based materials and for finding applications to basic research.