Ultra-elongated depth of focus of plasmonic lenses with concentric elliptical slits under Gaussian beam illumination  

作　　者：王婧 付永启 

机构地区：[1]School of Physical Electronics,University of Electronic Science and Technology of China

出　　处：《Chinese Physics B》2013年第9期209-213,共5页中国物理B（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 11079014 and 61077010)

摘　　要：In this paper, we discuss the influence of ratio of minor to major axis on the propagation property and focusing performance of a plasmonic lens with variant periodic concentric elliptical slits illuminating under a Gaussian beam. In order to analyse the influence theoretically, a finite-difference time-domain （FDTD） numerical algorithm is adopted for the computational numerical calculation and the design of the plasmonic structure. The structure is flanked with penetrated slits through a 200-nm metal film （Au） which is coated on a quartz substrate. Tunability of focusing capability of the plasmonic lenses is studied by tailoring the ratio. Our calculation results demonstrate that the ratio of the elliptical slits greatly affects the focusing capability of the lense. The plasmonic lenses with concentric elliptical slits illuminating under a Gaussian beam have ultra-elongated depth of focus. These results are very encouraging for the future study of the plasmonic lens-based applications.In this paper, we discuss the influence of ratio of minor to major axis on the propagation property and focusing performance of a plasmonic lens with variant periodic concentric elliptical slits illuminating under a Gaussian beam. In order to analyse the influence theoretically, a finite-difference time-domain （FDTD） numerical algorithm is adopted for the computational numerical calculation and the design of the plasmonic structure. The structure is flanked with penetrated slits through a 200-nm metal film （Au） which is coated on a quartz substrate. Tunability of focusing capability of the plasmonic lenses is studied by tailoring the ratio. Our calculation results demonstrate that the ratio of the elliptical slits greatly affects the focusing capability of the lense. The plasmonic lenses with concentric elliptical slits illuminating under a Gaussian beam have ultra-elongated depth of focus. These results are very encouraging for the future study of the plasmonic lens-based applications.

关 键 词：ultra-elongated depth of focus plasmonic lenses elliptical slits finite-difference time-domain 

分 类 号：TN011[电子电信—物理电子学]