Unidirectional surface plasmon-polariton excitation by a compact slot partially filled with dielectric

作者:Li Dongdong*; Zhang Dao Hua; Yan Changchun; Li Tao; Wang Yueke; Xu Zhengji; Wang Jun; Qin Fei
来源:Optics Express, 2013, 21(5): 5949-5956.
DOI:10.1364/OE.21.005949

摘要

We propose a new scheme on unidirectional surface plasmon-polariton (SPP) excitation with the following advantages: ultracompact size, working at arbitrary incidence angle and over a wide spectrum. The proposed structure utilizes a partially filled metallic slot with dielectric to realize unidirectional SPP excitation via direct field manipulation. We theoretically and numerically show that unidirectional SPP excitation with a ratio of 93% can be achieved by a structure with a 50 nm slot. The proposed structure keeps its functional capability over incident angles from -80 degrees to 80 degrees, and has a broadband working spectrum of more than 70 nm.