Subwavelength Focusing of Hybrid Ag-Au Plasmonic Lens with Variant Slit Widths

Abstract

We design the hybrid Ag-Au double-layered structure as plasmonic lens. The subwavelength focusing can be achieved with focal length within 500 nm. Furthermore, the focusing properties can be tuned by the thickness ratio of Ag/Au. Finally, we find the best of focusing effect as the thickness ratio is 1.