Vibrational spectroscopy is a powerful tool to reveal chemical structures and dynamics. However, the spatial resolution is restricted to be a few hundreds of nanometers to a few micrometers due to the diffraction limit. The rapid advancement of nanoscience and nanotechnology requires much a higher sensitivity and spatial resolution. We are developing nanoscale and even atomic-scale vibrational spectroscopy by combining state-of-the-art scanning probe microscopy with surface-enhanced spectroscopy that utilizes strong enhancement and confinement of light occurring in metallic nanostructures through localized surface plasmon excitation. Tip-enhanced Raman spectroscopy (TERS) uses “nanolight” generated at the apex of a sharp plasmonic tip. We have recently demonstrated tip-enhanced “resonance” Raman spectroscopy (TERRS) which has an exceptional high chemical sensitivity and spatial resolution, about ~1 nm. This technique will allow us to investigate chemical structures and dynamics of nano-materials and single-molecules on surfaces.
 S. Liu, et al. Nano Lett. 19, 5725 (2019).