Dual-path remote-excitation surface enhanced Raman microscopy with plasmonic nanowire dimer

Abstract

We demonstrate how a silver-nanowire-dimer can be employed to optically excite dual-path surface-plasmon-polaritons and utilize them to perform remote-excitation surface-enhanced Raman scattering (SERS) microscopy. Interestingly, this unique geometry allows us to perform dual-path remote-excitation SERS. Our experiments show that for the same value of excitation-laser powers, dual-path excitation leads to enhanced-SERS signal compared to single-path excitation, which has been corroborated by 3-D finite-difference time-domain simulations. Furthermore, we show that SERS-enhancement can be remotely modulated in this geometry by varying the polarization of excitation-fields. The results discussed herein can be extrapolated to remote-excitation pump-probe spectroscopy and dual-colour optical interrogation.