Gou Yue, Ma Hui Feng, Wang Zheng Xing, Wu Liang Wei, Wu Rui Yuan, Cui Tie Jun
Opt Express. 2022 Apr 11;30(8):12775-12787. doi: 10.1364/OE.453703.
The development of chiral metasurfaces with spin-selective reflection or transmission provides a new way to control the circularly polarized (CP) waves. However, it is still a great challenge to independently manipulate the polarization, frequency, and phase of the spin-selective reflected waves in different operating bands, which may have potential applications in improving the data capacity of microwave and optical communication systems. Here, a dual-band chiral metasurface is proposed to generate gigantic intrinsic chirality with strong circular dichroism (CD) in two different frequency bands by piecing two typical mono-chiral units together. The polarization, frequency and phase of the spin-selective reflected waves can also be independently designed in the two operating bands by adjusting the configuration of the chiral unit structures. Based on the proposed chiral structures, a dual-band chiral metasurface with spin-selective anomalous reflections is designed and demonstrated by both simulations and experiments. The results show that the polarization of spin-selective reflected waves can be customized by selecting appreciate chiral structures, while the wavefront of the spin-selective reflected waves can be further controlled by designing their arrangement.
具有自旋选择性反射或透射的手性超表面的发展为控制圆极化（CP）波提供了一种新方法。然而，在不同工作频段独立操纵自旋选择性反射波的极化、频率和相位仍然是一个巨大的挑战，这在提高微波和光通信系统的数据容量方面可能具有潜在应用。在此，提出了一种双频段手性超表面，通过将两个典型的单手性单元拼接在一起，在两个不同频段产生具有强圆二色性（CD）的巨大固有手性。通过调整手性单元结构的配置，还可以在两个工作频段独立设计自旋选择性反射波的极化、频率和相位。基于所提出的手性结构，通过仿真和实验设计并演示了一种具有自旋选择性异常反射的双频段手性超表面。结果表明，通过选择合适的手性结构可以定制自旋选择性反射波的极化，而通过设计其排列可以进一步控制自旋选择性反射波的波前。
