Investigating the characteristics of the electromagnetic field generated inside plasmonically coupled metallic nanostructures with a small nanogap <1 nm is significantly important for the rational deign of plasmonic nanostructures with enormously enhanced electric field. Especially, plasmonic dimeric nanostructures have been heavily studied, mainly because of relatively easier structural reproducibility among the coupled multimeric nanostructures. However, controlling the geometrical structure with ~sub nm accuracy and the corresponding change in the magnitude of the electric field in a single dimeric nanostructure is still highly challenging, such that it is difficult to obtain reliable and reproducible surface-enhanced Raman scattering (SERS) signal essentially originating from the enhanced electric field inside the nanogap. This is indeed a critical issue because the SERS enhancement factors (EFs) exhibit a broad distribution (>10⁶) with a long population tail even within a single SERS hot-spot, which could be largely attributable to subtle change in the plasmonic nanostructures and the random orientation and position of an analyte molecule within the plasmonic hot spot. Therefore, it is of paramount importance to systematically investigate a relationship between the geometry of nanostructure and the optical signals at the singlemolecule and single-particle levels.

Date Published: 28 August 2014
PDF: 4 pages
Proc. SPIE 9169, Nanoimaging and Nanospectroscopy II, 916906 (28 August 2014); doi: 10.1117/12.2062558

Published in SPIE Proceedings Vol. 9169:
Nanoimaging and Nanospectroscopy II
Prabhat Verma; Alexander Egner, Editor(s)