Near-Field Raman Enhancement of Single Molecules and Point Scatterers

Sandro Mignuzzi*, Fumin Huang, Debdulal Roy, David Richards

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Tip-enhanced Raman spectroscopy (TERS) is an emerging tool to characterize low-dimensional materials requiring high spatial resolution beyond the light diffraction limit. The most extreme example of a spatially localized scatterer is that of a zero-dimensional system, e.g., a single molecule, a nanoparticle, or an individual defect within a crystal. Here, using an analytical model for near-field Raman scattering from point-like structures in the presence of a plasmonic metal probe, we investigate the TERS patterns of representative single molecules with arbitrary orientation, for a range of Raman tensor symmetries. The results can be used to determine the orientation of single molecules as well as to differentiate molecules with diverse Raman tensors or, conversely, Raman modes with different Raman tensors from the same molecule. To demonstrate that the model is of general applicability to any spatially localized Raman modes, we further apply it to TERS imaging of individual point defects in graphene, unveiling the dependence of field enhancement and spatial resolution on the Raman mode symmetry, incident field polarization, and angle of the near-field probe.

Original languageEnglish
Pages (from-to)18800-18806
JournalJournal of Physical Chemistry C
Issue number34
Early online date01 Aug 2017
Publication statusPublished - 31 Aug 2017

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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