Low-loss plasmonic waveguide based on gain-assisted periodic metal nanoparticle chains

We have theoretically studied low transmission loss nanoscale waveguide based on gain-assisted plasmonic resonance metallic nanoparticle chain. We demonstrate that by employing a gain material or even an appropriate dielectric for the host environment, waveguide loss can be reduced dramatically and efficient energy splitter can be realized. We developed a highly efficient pseudo-orthonormal basis expansion method for obtaining the complex dielectric spectra of the low-loss transmission. Eigenmode analysis revealed the physical origin of those low-loss waveguiding modes, which opens the possibility to achieve waveguiding other than using conventional dipolar resonances of individual particles. The proposed host medium can be satisfied by semiconductor materials, laser dyes or optical glass.