论文标题
通过紧密聚焦的高阶矢量梁在等离子体纳米antennas中有效的杂种模式激发
Efficient hybrid-mode excitation in plasmonic nanoantennas by tightly focused higher-order vector beams
论文作者
论文摘要
纳米antennas中杂交等离子体模式的有效光激发对于实现许多有前途的功能至关重要，但是由于入射光和混合模式之间的现场核心不匹配，这可能是具有挑战性的。我们通过以各种高阶螺旋相的圆柱极化矢量束聚焦入射光场来提出一种通用方法来进行有效的杂种激发。在高阶极化状态和Stokes参数（均定义在极性坐标中定义）中描述了这种基矢量梁，并在高阶Poincaré球体上相应地观察到。该焦距仅在圆柱坐标中作为相关高阶近轴束的所有聚焦梁的一系列总和进行配制。我们的焦距分解可以通过高阶矢量梁对混合模式激发进行分析，从而在紧密焦点的区域中简单地设计有效模式匹配场谱。
Efficient optical excitation of hybridized plasmon modes in nanoantennas is vital to achieve many promising functionalities, but it can be challenging due to a field-profile mismatch between the incident light and the hybrid mode. We present a general approach for efficient hybrid-mode excitation by focusing the incident light field in the basis of cylindrically polarized vector beams of various higher-order spiral phases. Such basis vector beams are described in the higher-order polarization states and Stokes parameters (both defined locally in polar coordinates), and visualized correspondingly on the higher-order Poincaré spheres. The focal field is formulated exclusively in cylindrical coordinates as a series sum of all focused beams of the associated high-order paraxial beams. Our focal field decomposition enables an analysis of hybrid-mode excitation via higher-order vector beams, and thus yields a straightforward design of effective mode-matching field profile in the tightly focused region.
