Optimization on Plasmonic Lenses Based on Generation Efficiency of Surface Plasmon Polaritons at Metallic Nanoslit

Abstract

The generation efficiency of surface plasmon polaritons at metallic nanoslit is theoretically analyzed, and a novel plasmonic lens with two semiannular nanoslits is proposed in this paper. Based on the analysis results, the focusing performance of the proposal is optimized with a maximum field intensity enhancement factor of 7.69 and the full width at half maximum is 132 nm (~0.2λ i ), far beyond theoretical diffraction limit. Meanwhile, some other classical plasmonic lenses are also optimized through improving generation efficiency of surface plasmon polaritons at nanoslit and the focusing performances are consequently greatly enhanced.