Cao Han, Yuan Rui, Xu Chunting, Zhang Yiheng, Hu Wei
Opt Lett. 2021 Nov 15;46(22):5751-5754. doi: 10.1364/OL.443894.
The introduction of spin and orbital angular momentum mode division multiplexing to existing wavelength division multiplexing will significantly enlarge the capacity of optical networks. Therefore, components compatible with the above techniques are in high demand. Here, a geometric phase combined a Dammann vortex grating, and a polarization grating is designed and encoded to a dual-twist reactive mesogen. It can generate a couple of vortex channel arrays highly efficiently in broadband. Meanwhile, orthogonal spins are spatially separated, facilitating spin identification. A vortex will recover to a Gaussian beam when it is diffracted to an order with opposite topological charge, which enables the detection of orbital angular momentum. It supplies a parallel and efficient way for decoupled spin and orbital angular momentum detection operating at the entire visible range, and the design may be extended to many other compatible optical communication components.
将自旋和轨道角动量模式分割复用引入现有的波分复用技术，将显著扩大光网络的容量。因此，对与上述技术兼容的组件有很高的需求。在此，设计了一种将几何相位与达曼涡旋光栅和偏振光栅相结合，并编码到双扭曲反应性液晶元中的结构。它能够在宽带内高效地产生一对涡旋通道阵列。同时，正交自旋在空间上分离，便于自旋识别。当一个涡旋衍射到具有相反拓扑电荷的级次时，它将恢复为高斯光束，这使得能够检测轨道角动量。它为在整个可见光范围内进行解耦的自旋和轨道角动量检测提供了一种并行且高效的方法，并且该设计可以扩展到许多其他兼容的光通信组件。
