Lee Dukhyung, Kim Dai-Sik
Department of Physics and Astronomy and Center for Atom Scale Electromagnetism, Seoul National University, Seoul 08826, Republic of Korea.
Sci Rep. 2016 Jan 7;6:18935. doi: 10.1038/srep18935.
We study light scattering off rectangular slot nano antennas on a metal film varying incident polarization and incident angle, to examine which field vector of light is more important: electric vector perpendicular to, versus magnetic vector parallel to the long axis of the rectangle. While vector Babinet's principle would prefer magnetic field along the long axis for optimizing slot antenna function, convention and intuition most often refer to the electric field perpendicular to it. Here, we demonstrate experimentally that in accordance with vector Babinet's principle, the incident magnetic vector parallel to the long axis is the dominant component, with the perpendicular incident electric field making a small contribution of the factor of 1/|ε|, the reciprocal of the absolute value of the dielectric constant of the metal, owing to the non-perfectness of metals at optical frequencies.
我们研究了金属薄膜上矩形缝隙纳米天线的光散射，改变入射光的偏振和入射角，以考察光的哪个场矢量更为重要：垂直于矩形长轴的电矢量与平行于矩形长轴的磁矢量。虽然矢量巴比涅原理倾向于沿长轴的磁场以优化缝隙天线功能，但传统观念和直觉通常指向垂直于长轴的电场。在此，我们通过实验证明，根据矢量巴比涅原理，平行于长轴的入射磁矢量是主导分量，垂直入射的电场由于金属在光频下的非完美性，仅贡献了金属介电常数绝对值倒数1/|ε|的一小部分。
