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.

Nanowire-supported plasmonic waveguide for remote excitation of surface-enhanced Raman scattering

“…Kumar's group has conducted interesting studies in local and remote SERS in an Ag nanowire dimer system in the last two years. 63,87 In the previous reports on remote SERS, a single laser beam was focused through a microscope to excite PSPPs in remote systems, which could be called single-path excitation. In their reports on remote SERS in Ag nanowire dimer systems, two laser beams were simultaneously focused at the terminals of different nanowires, which was called dual-path excitation, to obtain the PSPPs that were eventually converted into radiating free photons at the end-to-end junction ( Figure 12 compared to that in single-path excitation at the same junction for equal values of excitation-laser powers.…”

“…[59][60][61]63,64 Specifically, it has been treated as a novel, powerful sensing technology to monitor bioreactions in vivo in cells. 59,60 Although this interesting design has not been realized yet, we introduce some exploratory work here to provide a method of improvement.…”

“…In this review, we first illustrate the synthesis and fabrication of metallic nanowires and the corresponding physical mechanism of the plasmonic waveguide. Second, various remote metal systems, such as a nanoparticle-nanowire system, 60 single nanowire system, 61 crossed nanowires system, 62 nanowire dimer system 63 Figure 1 A sketch of the local SERS and the remote SERS in an Ag nanoparticle-nanowire system (Raman molecule adsorbed on the Ag nanowire). The Raman signals obtained at the illuminating terminal are local SERS, while the signals collected at the junction whose energy come from the propagating SPPs are remote SERS.…”

Spatial Distribution of the Nonlinear Photoluminescence in Au Nanowires

“…Nanowires are considered as suitable candidates for subwavelength confining, tailoring and guiding optical signals in highly integrated optical circuits 15,16 and its plasmonic modal decomposition is easy to predict. 17,18 Importantly, metal nanowires have been deployed to remotely excite and detect various optical processes like Raman scattering 19,20 and up-converted luminescence from a distant crystal. 21 Here we focus at spatially resolving the spectral signature of the broadband nonlinear up-converted emission in gold nanowires (AuNWs).…”

Recent advances in surface plasmon-driven catalytic reactions

“…Currently, remote excitation surface-catalytic reduction has also been realized by propagating plasmons. [77][78][79] A plasmon waveguide used as a nanoantenna can induce 4-NBT to DMAB at a junction due to the massive EM eld contribution. Fig.…”