Plasmon assisted light propagation and Raman scattering hot-spot in end-to-end coupled silver nanowire pairs

Abstract

Herein, we report on the experimental observation of light propagation and localization capabilities of end-to-end connected silver nanowire (Ag NW) pairs. By exciting the surface plasmon polaritons at one end of Ag NW pair, we observed relatively intense light emission at the junction and weak light emission at the distal end of the pair. To probe the localization of light at nanowire junction, we captured far-field Raman image of an isolated Ag NW pair adsorbed with rhodamine 6 G and observed enhanced Raman scattering at the nanowire junction. Such nanophotonic modules with light propagation and localization capabilities can be harnessed for multiplexed on-chip plasmonics.

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.…”

Propagation of light in serially coupled plasmonic nanowire dimer: Geometry dependence and polarization control

“…1(c)), is a plasmonic hotjunction for surface enhanced optical spectroscopy. 15 The schematic in Fig. 1(d) shows the experimental configuration.…”

“…The advantage of this serial coupling configuration is that minimal area of the nanowire is utilized for connection, thereby leaving the lengths of the nanowire for further utility and coupling. This unique geometry can facilitate light propagation along the nanowires and localization at the nanowire junctions on a single nanophotonic platform, 15 and hence very useful in building nano-plasmonic circuits.…”

“…Ag NWs have been previously studied in the context of nano-waveguides, [8][9][10][11][12][13][14][15][16] optical logical gates, 17 quantum optics, 10 surface enhanced Raman scattering (SERS), 15,[18][19][20] fluorescence, 21 chiral plasmons 22 etc., indicating their versatility as nanophotonic element. In this study, we employ an end-to-end coupled Ag NW dimer and investigate their plasmon-mediated light propagation and emission properties.…”

“…15 The details of fabrication procedure and optical measurement can be found in Secs. S1 and S2 of the supplementary information (SI).…”