No Arabic abstract
We propose a scheme to obtain a low-loss propagation of Airy surface plasmon polaritons (SPPs) along the interface between a dielectric and a negative-index metamaterial (NIMM). We show that, by using the transverse-magnetic mode and the related destructive interference effect between electric and magnetic absorption responses, the propagation loss of the Airy SPPs can be largely suppressed when the optical frequency is close to the lossless point of the NIMM. As a result, the Airy SPPs obtained in our scheme can propagate more than 6-time long distance than that in conventional dielectric-metal interfaces.
We have observed laser-like emission of surface plasmon polaritons (SPPs) decoupled to the glass prism in an attenuated total reflection setup. SPPs were excited by optically pumped molecules in a polymeric film deposited on the top of the silver film. Stimulated emission was characterized by a distinct threshold in the input-output dependence and narrowing of the emission spectrum. The observed stimulated emission and corresponding to it compensation of the metallic absorption loss by gain enables many applications of metamaterials and nanoplasmonic devices.
We propose a scheme to realize a lossless propagation of linear and nonlinear Airy surface polaritons (SPs) via active Raman gain (ARG). The system we suggest is a planar interface superposed by a negative index metamaterial (NIMM) and a dielectric, where three-level quantum emitters are doped. By using the ARG from the quantum emitters and the destructive interference effect between the electric and magnetic responses from the NIMM, we show that not only the Ohmic loss of the NIMM but also the light absorption of the quantum emitters can be completely eliminated. As a result, non-diffractive Airy SPs may propagate for very long distance without attenuation. We also show that the Kerr nonlinearity of the system can be largely enhanced due to the introduction of the quantum emitters and hence lossless Airy surface polaritonic solitons with very low power can be generated in the system.
The interference patterns of the surface plasmon polaritons(SPPs) on the metal surface from a point source are observed. These interference patterns come from the forward SPPs and the reflected one from the obstacles, such as straightedge,corner, and ring groove structure. Innovation to the previous works, a point SPPs source with diameter of 100 nm is generated at the freely chosen positions on Au/air interface using near field excitation method. Such a point source provides good enough coherence to generate obvious interference phenomenon. The constructive and destructive interference patterns of the SPPs agree well with the numerical caculation. This point SPPs source may be useful in the investigation of plasmonics for its high coherence, deterministic position and minimum requirement for the initial light source.
Nonreciprocity and one-way propagation of optical signals is crucial for modern nanophotonic technology, and is typically achieved using magneto-optical effects requiring large magnetic biases. Here we suggest a fundamentally novel approach to achieve unidirectional propagation of surface plasmon-polaritons (SPPs) at metal-dielectric interfaces. We employ a direct electric current in metals, which produces a Doppler frequency shift of SPPs due to the uniform drift of electrons. This tilts the SPP dispersion, enabling one-way propagation, as well as zero and negative group velocities. The results are demonstrated for planar interfaces and cylindrical nanowire waveguides.
Controlling the directionality of surface plasmon polaritons (SPPs) has been widely studied, while the direction of SPPs was always switched by orthogonal polarizations in the reported methods. Here, we present a scheme to control the directionality of SPPs by arbitrary spin polarizations. Extremely, the device can split two quite adjacent polarization components to two opposite directions. The versatility of the presented design scheme can offer opportunities for polarization sensing, polarization splitting and polarization-controlled plasmonic devices.