Scattering-type scanning near-field optical microscopy (s-SNOM) is a robust method for visualizing the optical response of surfaces with a spatial resolution down to 10 nm. Near-field signal detection relies on lock-in harmonic demodulation referring to tip oscillation driven by atomic force microscopy (AFM). The improvement of the spatial resolution requires stabilizing the sub-nanometer-scale tip-sample junction and improving the duty cycle of the near-field detection using a low tapping amplitude. [more...]

Molecular hydrogen is a key renewable energy material, and its adsorption on solid surfaces is important for its storage, transport, and catalytic reactions. Characterizing the structure and dynamics of these small and fast-diffusing molecules weakly adsorbed (physisorbed) on metallic surfaces has long been a major challenge. We investigate hydrogen molecules on a silver surface and demonstrate that low-temperature tip-enhanced Raman spectroscopy (LT-TERS) reveals the vibrational and rotational properties of the physisorbed molecule [more...]