Point-Contact Tip-Enhanced Raman Spectroscopy: Picoscale Light–Matter Interactions within Plasmonic Cavities

Takashi Kumagai^1*

¹Center for Mesoscopic Sciences, Institute for Molecular Science, Okazaki, Japan

* Presenter:Takashi Kumagai, email:kuma@ims.ac.jp

Near-field Raman spectroscopy has become a versatile tool in nanoscience and nanotechnology. Recent advances in tip-enhanced Raman spectroscopy (TERS), performed under ultrahigh vacuum and low-temperature conditions, have enabled atomic-scale Raman imaging through precise control of sub-nanometer plasmonic fields. This technique has opened access to previously unattainable regimes of Raman scattering. In this talk, I will focus on Raman scattering of quantum point contacts formed by a single atom or molecule, which serves as an intriguing platform not only for atomic-scale chemical analysis but also for exploring light–matter interactions in nonequilibrium quantum systems such as single-molecule junctions. Point-contact TERS reveals that Raman scattering is sensitive to picoscale structural variations, providing indispensable insight into the emerging field of picocavity science.

Keywords: Surface Science, Near-Field Optics, Tip-Enhanced Raman Spectroscopy, Plasmonic Picocavity, Atomic/Molecular Point Contact