Opt Express. 2022 Nov 21;30(24):43728-43740. doi: 10.1364/OE.477586.
In this paper, by elaborately splicing multiple transmissive metasurfaces (MSs) featuring polarization isolation, multiple linear polarized (LP) vortex beams are generated simultaneously and independently in different directions. Specifically, by carefully optimizing the radius of the array and the distance between the MS and array, each MS generates a well-performed deflection vortex beam with a low side-lobe level and little diffraction, resulting in a minor effect on other deflection vortex beams. Subsequently, four transmissive MSs are elaborately spliced, showing the polarization isolation characteristic between the adjacent MS, and thereby each MS is only illuminated by the respective antenna array. In addition, each MS only generates the desired LP vortex beam, and the corresponding cross-polarization is suppressed. Finally, the simulation and measurement results show that multiple LP vortex beams carrying different orbital angular momentum (OAM) modes are generated simultaneously and independently in different directions, verifying the effectiveness of the proposed method.
在本文中，通过精心拼接多个具有偏振隔离特性的透射超表面（MS），可以在不同方向上同时且独立地产生多个线偏振（LP）涡旋光束。具体来说，通过仔细优化阵列的半径和 MS 与阵列之间的距离，每个 MS 都会产生一个具有低旁瓣水平和小衍射的性能良好的偏折涡旋光束，对其他偏折涡旋光束的影响较小。然后，精心拼接四个透射 MS，展示出相邻 MS 之间的偏振隔离特性，从而每个 MS 仅由各自的天线阵列照射。此外，每个 MS 仅生成所需的 LP 涡旋光束，并抑制相应的交叉极化。最后，仿真和测量结果表明，多个携带不同轨道角动量（OAM）模式的 LP 涡旋光束在不同方向上同时且独立地产生，验证了所提出方法的有效性。
