Investigation of Focusing Characteristics of Plasmonic Lenses with Concentric Elliptical Slits

Abstract

In this paper, we discussed the influence of different ratios of minor to major axis and polarizations of incident wave on the propagation properties and focusing performance of a plasmonic lens with variant periodic concentric elliptical slits. In order to analyze the influence theoretically, a finite-difference time-domain numerical algorithm (FDTD) was adopted for computational numerical calculation and design of the plasmonic structures. The structures are flanked with penetrated slits through a 200 nm metal film (Au) which was coated on a quartz substrate. Tunability of focusing capability of the plasmonic lenses was studied by means of tailoring the ratio and polarization state. Our calculation results demonstrated that different ratios of the elliptical slits greatly affect the focusing capability of the lenses. Polarization state has influence on the propagation properties and focusing performance. These results are very encouraging for future study of the plasmonic lens-based applications. Copyright 2013 American Scientific Publishers.