Wang Shiyi, Abeysinghe Don C, Zhan Qiwen
Opt Lett. 2015 Oct 15;40(20):4711-4. doi: 10.1364/OL.40.004711.
A transmission-type metasurface composed of carefully designed rectangular slot antennas for the generation of vectorial optical fields is proposed and demonstrated. Acting as local linear polarizers, these slot antennas enable the spatial modulation of optical fields in amplitude, phase, and polarization for the cross-polarized component of the scattered field. As an illustration, a metasurface capable of forming a radially polarized scattered field with specific vectorial beam patterns with appropriate excitation at normal incidence is designed, fabricated, and tested. The radially polarized scattered field is designed to be further tightly focused by a high numerical aperture objective lens in order to obtain a uniform longitudinally polarized optical needle field along the propagation direction. Characterization experiments demonstrate that its overall extinction ratio satisfies the amplitude modulation requirement, and a corresponding π phase modulation is realized as proposed.
提出并演示了一种由精心设计的矩形缝隙天线组成的透射型超表面，用于产生矢量光场。作为局部线性偏振器，这些缝隙天线能够对散射场的交叉偏振分量的光场进行幅度、相位和偏振的空间调制。作为示例，设计、制作并测试了一种超表面，该超表面在垂直入射时通过适当的激发能够形成具有特定矢量光束图案的径向偏振散射场。径向偏振散射场被设计为由高数值孔径物镜进一步紧密聚焦，以便沿传播方向获得均匀的纵向偏振光针场。表征实验表明，其整体消光比满足幅度调制要求，并如所提出的那样实现了相应的π相位调制。
