Department of Materials Science, Laboratory of Advanced Materials and Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Fudan University, Shanghai 200433, China.
Sci Rep. 2016 Aug 26;6:32345. doi: 10.1038/srep32345.
Conventional plasmonic lenses are composed of curved slits carved through metallic films. Here, we propose a new plasmonic lens based on a metallic slit with an auxiliary groove. When the lens is illumined normally, only inward surface plasmon polaritons (SPPs) can be generated and then focused into a hot spot at the center of the lens. The focusing effect is theoretically investigated by varying the groove parameters and incident polarizations. It is found that this phenomenon exists for both the circular and linear polarizations of incidence. Under optimal groove parameters, the intensity of the focal spot in our lens can be 2.5 times of that in one without grooves for both linearly and circularly polarized illuminations.
传统的等离子体透镜由通过金属膜雕刻而成的弯曲狭缝组成。在这里，我们提出了一种基于具有辅助槽的金属狭缝的新型等离子体透镜。当透镜被正常照亮时，只能产生向内的表面等离激元极化激元（SPP），然后将其聚焦到透镜中心的一个热点上。通过改变槽参数和入射偏振来理论研究聚焦效果。发现这种现象对于入射的圆偏振和线偏振都存在。在最佳槽参数下，对于线偏振和圆偏振照明，我们的透镜中的焦点强度可以分别达到没有槽的透镜的 2.5 倍。
