Photonic spin and orbital angular momenta, which are determined by the polarization and spatial degrees of freedom of photons, are strongly coupled with each other in subwavelength structured metasurfaces. The photonic spin-orbit interaction (PSOI) results in the splitting of the degenerated system states. In this review, we focus on the principles of symmetric PSOI associated with the conjugated geometric phase modulation as well as the asymmetric PSOI resulting from the additional localized phase manipulation. Recent advances and important applications of symmetric and asymmetric PSOI in metasurfaces are also discussed. We finally highlight with our perspective on the remaining challenges and future trends in this field.

由光子的偏振和空间自由度决定的光子自旋和轨道角动量在亚波长结构的超表面中相互强烈耦合。光子自旋轨道相互作用 (PSOI) 导致退化系统状态的分裂。在这篇综述中，我们关注与共轭几何相位调制相关的对称 PSOI 的原理，以及由附加局部相位操作产生的非对称 PSOI。还讨论了对称和非对称 PSOI 在超表面中的最新进展和重要应用。我们最后强调了我们对该领域剩余挑战和未来趋势的看法。