Opt Lett. 2018 Jun 1;43(11):2474-2477. doi: 10.1364/OL.43.002474.
Spin-orbit interactions are subwavelength phenomena that can potentially lead to numerous device-related applications in nanophotonics. Here, we report the spin-Hall effect in the forward scattering of Hermite-Gaussian (HG) and Gaussian beams from a plasmonic nanowire. Asymmetric scattered radiation distribution was observed for circularly polarized beams. Asymmetry in the scattered radiation distribution changes the sign when the polarization handedness inverts. We found a significant enhancement in the spin-Hall effect for a HG beam compared to a Gaussian beam for constant input power. The difference between scattered powers perpendicular to the long axis of the plasmonic nanowire was used to quantify the enhancement. In addition, the nodal line of the HG beam acts as the marker for the spin-Hall shift. Numerical calculations corroborate experimental observations and suggest that the spin flow component of the Poynting vector associated with the circular polarization is responsible for the spin-Hall effect and its enhancement.
自旋轨道相互作用是亚波长现象，有可能在纳米光子学中导致许多与器件相关的应用。在这里，我们报告了在等离子体纳米线的前向散射中，厄米-高斯（HG）光束和高斯光束的自旋霍尔效应。对于圆偏振光束，观察到了不对称的散射辐射分布。当偏振手性反转时，散射辐射分布的不对称性会改变符号。我们发现，与高斯光束相比，HG 光束在恒定输入功率下的自旋霍尔效应显著增强。通过比较垂直于等离子体纳米线长轴的散射功率，可以定量地衡量增强效果。此外，HG 光束的节点线充当自旋霍尔位移的标记。数值计算证实了实验观察结果，并表明与圆偏振相关的电磁矢势的自旋流分量是自旋霍尔效应及其增强的原因。
