Guangzhou Key Laboratory for Special Fiber Photonic Devices and Applications, South China Normal University, Guangzhou, 510006, China.
Nanoscale. 2017 Apr 13;9(15):4944-4949. doi: 10.1039/c7nr00124j.
The tunable orbit angular momentum (OAM) of surface plasmon polaritons (SPPs) is theoretically studied with appropriately designed metasurfaces. By controlling both the orientation angle and the spatial position of a nano aperture array on an ultrathin gold film, the field distributions of the surface waves can be engineered to contain both spin dependent and independent OAM components. Simultaneous control over the geometric phase and the optical path difference induced phase (dynamic phase) provides extra degrees of freedom for manipulating the OAM of SPPs. We show that an arbitrary combination of OAM numbers can be realized for the SPPs excited by incident light of different circular polarizations. Our results provide powerful control over the OAM of SPPs, which will have potential applications in optical trapping, imaging, communications and even quantum information processing.
本文理论研究了通过适当设计超表面来实现表面等离激元（SPP）的可调轨道角动量（OAM）。通过控制超薄金膜上纳米孔径阵列的取向角和空间位置，可以对表面波的场分布进行工程设计，使其包含自旋相关和独立的 OAM 分量。对几何相位和由光程差引起的相位（动态相位）的同时控制为操纵 SPP 的 OAM 提供了额外的自由度。我们表明，对于不同圆偏振光激发的 SPP，可以实现任意 OAM 数的组合。我们的研究结果为 SPP 的 OAM 提供了强大的控制手段，这将在光学捕获、成像、通信甚至量子信息处理等领域具有潜在的应用价值。
