Reproducible Ultrahigh Electromagnetic SERS Enhancement in Nanosphere-Plane Junctions

Abstract

Surface enhanced Raman scattering (SERS) in nanoscale hotspots has been placed great hopes upon for identification of minimum chemical traces and in-situ investigation of single molecule structures and dynamics. However, previous work consists of either irreproducible enhancement factors (EF) from random aggregates, or moderate EFs despite better reproducibility. Consequently, systematic study of SERS at the single and few molecules level is still very limited, and the promised applications are far from being realized. Here we report EFs as high as the most intense hotspots in previous work yet achieved in a reproducible and well controlled manner, that is, electromagnetic EFs (EMEF) of 10^9~10 with an error down to 10^+/-0.08 from gold nanospheres on atomically flat gold planes under radially polarized (RP) laser excitation. In addition, our experiment reveals the EF's unexpected nonlinearity under as low as hundreds of nanowatts of laser power.

arXiv comment21 pages, 8 figures

References in corpus (4)

• Plasmons in nearly touching metallic nanoparticles: singular response in the limit of touching dimers
• Simultaneous measurements of electronic conduction and Raman response in molecular junctions
• Molecular cavity optomechanics: a theory of plasmon-enhanced Raman scattering
• Controlling Sub-nm Gaps in Plasmonic Dimers using Graphene

Cited by in corpus (4)

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• 2D-Material-Assisted Bistable Switching of Gap Plasmons Disclosed By Femtosecond Pulse Scattering Spectra
• Quadruple-enhanced four-wave mixing in nanometer plasmonic hotspots: classical theory and experiments