Zheng Chenglong, Li Jie, Wang Guocui, Wang Silei, Li Jitao, Zhao Hongliang, Zang Huaping, Zhang Yan, Zhang Yating, Yao Jianquan
Key Laboratory of Opto-Electronics Information Technology (Tianjin University), Ministry of Education, School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, No. 92 WeiJin Road, Tianjin, 300072, China.
Nanoscale. 2021 Mar 21;13(11):5809-5816. doi: 10.1039/d1nr00376c. Epub 2021 Mar 12.
Integrating independent wavefront controls into one device can meet the increasing demand for high-capacity flat electromagnetic devices. Simultaneously and independently controlling the amplitude and phase is pivotal for completely manipulating the propagation of electromagnetic waves. Here, we propose several all-silicon metasurfaces to achieve multifunctional designs and simultaneous modulation of amplitude and phase profiles in the terahertz (THz) band. These metasurfaces integrate two degrees of freedom of the propagation phase and Pancharatnam-Berry (PB) phase. To illustrate the feasibility of this design, three schematic functions are shown below: a three-channel vortex beam generator, a controllable intensity ratio of co- and cross-polarizations corresponding to the incident circular polarization (CP), and a bifocal metasurface that is capable of generating two off-axis vortices with controllable power allocation. A sample is fabricated to specifically verify the amplitude and phase modulation of this design. The experimental results agree well with the simulations and validate the good performances of our proposals. This approach for directly generating an editable amplitude and phase may provide a new choice to design ultra-thin photonic devices.
将独立的波前控制集成到一个设备中，可以满足对高容量平面电磁设备日益增长的需求。同时独立地控制幅度和相位对于完全操纵电磁波的传播至关重要。在此，我们提出了几种全硅超表面，以实现太赫兹（THz）波段的多功能设计以及幅度和相位分布的同时调制。这些超表面集成了传播相位和庞加莱 - 贝里（PB）相位的两个自由度。为了说明这种设计的可行性，下面展示了三个示意性功能：一个三通道涡旋光束发生器、一个与入射圆偏振（CP）对应的共偏振和交叉偏振的可控强度比，以及一个能够产生两个具有可控功率分配的离轴涡旋的双焦超表面。制作了一个样品以专门验证这种设计的幅度和相位调制。实验结果与模拟结果吻合良好，验证了我们方案的良好性能。这种直接生成可编辑幅度和相位的方法可能为设计超薄光子器件提供新的选择。
