Abstract
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.
Highlights
Location, the propagation behaviour of SPPs is controlled and results in the switch power between the two NW branches
We find that the emission intensity at NP is related to the strength of the local SPPs field in NW and the intensity at NW end is mainly dependent on the distance between NW terminal and excitation end
It is interesting to note that the emission intensity at NP shows an exponential decay trend with an undulating pattern, while the intensity at NW end is almost a constant value when NP is gradually moved from the excitation end to NW end
Summary
Location, the propagation behaviour of SPPs is controlled and results in the switch power between the two NW branches. The precise and flexible control over the NP position in NW-based waveguides is a significant and meaningful issue for the development of nanophotonic devices. We realize the control of SPPs propagation properties in Ag NW through continuously tuning the position of Ag NP along the NW. We investigate the change of the emission intensities at NP and NW end with tuning the NP position. Instead of tuning the NP position, we investigate the emission behaviour in NP-NW geometry through changing the position of excitation, and study the change of propagation loss at different NP locations. Our results indicate the significant role of NP position in NW-based waveguides and shed light on the structural design of future nanophotonic devices
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