scattering-suppressed plasmonic bends and adapters with gradient refractive index medium

We propose the designs of plasmonic bends and adapters with low scattering loss in visible region theoretically. tens of nanometers thick gradient refractive index medium is deposited on the metallic surface, which can confine and release the surface plasmon polaritons (spps). when spps can be strongly confined the metallic surface and propagate along the corners of the plasmonics devices, the scattering loss can be dramatically suppressed. full wave simulations based on a finite element method have been performed to validate our proposal. compared with the same class of design, our method can be achieved only with isotropic materials.