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O: Fachverband Oberflächenphysik
O 12: Scanning Probe Techniques: Method Development I
O 12.7: Talk
Monday, March 27, 2023, 16:30–16:45, GER 37
Development of SNOM combining plasmonic picocavities with noncontact AFM — •Akitoshi Shiotari1, Jun Nishida2, Adnan Hammud1, Martin Wolf1, Takashi Kumagai2, and Melanie Müller1 — 1Fritz-Haber Institute of the Max-Planck Society, Berlin, Germany — 2Institute for Molecular Science, Okazaki, Japan
Scattering-type scanning near-field optical microscopy (s-SNOM) is a powerful tool to visualize the nanoscale optical response of sample surfaces. However, the resolution of conventional s-SNOM is usually limited by thermal instabilities of the tip-apex structure and the weak light intensities scattered from small volumes. On the other hand, it has been shown recently that light can be confined to the atomic scale using plasmonic picocavities. Here we demonstrate the development of plasmonic s-SNOM based on noncontact atomic force microscopy (nc-AFM) under the low-temperature and ultrahigh-vacuum conditions. A quartz tuning fork sensor with a Ag tip sharpened by focused ion beam milling enables precise control of the subnanometer tip-sample gap under illumination with visible laser light. The extremely high field enhancement and localization of light in the picocavity enhances the scattered light intensity and allows to image the optical response of samples at 1 nm resolution. The combination of ncAFM with plasmonic picocavities has high potential for atomic resolution optical imaging of various materials, including insulators.