A Long-Range Surface Plasmon Resonance/Probe/Silver Nanoparticle (LRSPR-P-NP) Nanoantenna Configuration for Surface-Enhanced Raman Scattering

Abstract

The purpose of this paper is to enhance Raman signals with a plasmonic nanoantenna based on a long-range surface plasmon resonance/probe/silver nanoparticle (LRSPR-P-NP) sandwich configuration. The finite-difference time-domain simulation shows that the electromagnetic field at the gap between the silver film and a silver nanoparticle increases by a factor of about 2.1 × 10⁴. The resonance condition of this plasmonic nanoantenna was optimized by incident angle-dependent surface-enhanced Raman scattering (SERS) spectroscopy under an evanescent field excitation mode. The SERS signal obtained under the LRSPR-P-NP configuration at the LRSPR angle was 40 times higher than that collected on the planar film plasmonic nanoantenna. The enhancement factor of the LRSPR-P-NP configuration was 9.2 × 10⁸. This plasmonic nanoantenna was also applied for pH sensing