Li Guoqun, Sun Yuqing, Wang Sen
Shandong Provincial Engineering and Technical Center of Light Manipulations & Shandong Provincial Key Laboratory of Optics and Photonic Device, College of Physics and Electronics, Shandong Normal University, Jinan, 250014, China.
Nanoscale Res Lett. 2019 May 7;14(1):156. doi: 10.1186/s11671-019-2990-2.
For the semicircular plasmonic lens, the spiral phase is the origin of the spin-dependent surface plasmon polariton (SPP) focusing. By counterbalancing the spin-dependent spiral phase with another spiral phase or Pancharatnam-Berry phase, we realized the SPP focusing independent from the spin states of the excitation light. Analyses based on both Huygens-Fresnel principle for SPPs and numerical simulations prove that the position, intensity, and profile of the SPP focuses are exactly the same for different spin states. Moreover, the spin-independent SPP focusing is immune from the change of the radius, the central angle, and the shape of the semicircular slit. This study not only further reveals the mechanism of spin-dependent SPP devices but also provides effective approaches to overcome the influence of spin states on the SPPs field.
对于半圆形等离子体透镜，螺旋相位是自旋相关表面等离激元极化激元（SPP）聚焦的起源。通过用另一个螺旋相位或潘查拉特纳姆 - 贝里相位抵消自旋相关的螺旋相位，我们实现了与激发光自旋状态无关的SPP聚焦。基于惠更斯 - 菲涅耳原理对SPP的分析和数值模拟都证明，对于不同的自旋状态，SPP焦点的位置、强度和轮廓完全相同。此外，自旋无关的SPP聚焦不受半圆形狭缝半径、圆心角和形状变化的影响。这项研究不仅进一步揭示了自旋相关SPP器件的机制，还提供了有效的方法来克服自旋状态对SPP场的影响。
