Control on Surface Plasmon Polaritons Propagation Properties by Continuously Moving a Nanoparticle along a Silver Nanowire Waveguide

Surface plasmon polaritons (SPPs)-based nanowire waveguides possess potential applications for nanophotonic circuits. Precise control on the propagation of SPPs in metal nanowires is thus of significant importance. In this work, we report the control on SPPs propagation properties by moving a silver nanoparticle (Ag NP) along a silver nanowire (Ag NW). The emission intensity at NP can be attenuated to about 25% of the maximum emission value with increasing the distance between excitation end and NP. When NP is gradually moved away from excitation end, the intensity of emission light at Ag NP shows an exponential decay with a superposition of wavy appearance, while the emission at NW end is almost a constant value. It is found that the former is related to the local SPPs field distribution in NW, and the latter is dependent on the distance between excitation end and NW terminal. Moreover, the propagation loss in Ag NP-NW structure has been investigated. Our experiments demonstrate the important role of NP location in NW-based waveguides and provide an effective method of tuning scattering light in NW, which is instructive to design the future specialized function of SPPs-based nanophotonic circuits and devices.