Metalens is one kind of two-dimensional ultrathin lenses with subwavelength artificial structures that can focus light in a compact, flexible way. However, most strategies for designing metalenses only work on one specific spin state of light (i.e., either right- or left-circularly polarized light), hindering simultaneous control of both spins. Utilizing both the Pancharatnam-Berry phase and the propagation phase, we can rationally control the phase for each spin state of light. As proof-of-concept demonstrations, here we numerically and experimentally realize the independent focusing and manipulation of both spins of light by V-antenna metasurfaces, which can be regarded as the demonstration of the photonic spin Hall effect. Our multidimensional metalens is able to focus light of different spins at designated positions along both transverse and longitudinal directions. It can be used as a polarization analyzer to distinguish the polarization state of incident light. In addition, our multifunctional metalens can act either as a convex lens or an axicon, depending on the spin of light. The demonstrated multidimensional and multifunctional metalens has versatile potentials in spin-dependent nanophotonics, ranging from optical imaging and micro/nano-object manipulation to optical sensing.

中文翻译：

---

基于光子自旋霍尔效应的多维多功能金属感镜的实验演示

Metalens是一种具有亚波长人工结构的二维超薄透镜，可以以紧凑，灵活的方式聚焦光。然而，大多数设计金属传感器的策略仅在一种特定的自旋光状态下起作用（即，右旋或左旋圆偏振光），这阻碍了同时控制两种自旋。利用Pancharatnam-Berry相和传播相，我们可以为每个自旋光态合理地控制相位。作为概念验证的演示，我们在数字上和实验上实现了V天线超表面对光的两个自旋的独立聚焦和操纵，可以将其视为光子自旋霍尔效应的演示。我们的多维金属素能够将不同自旋的光聚焦在沿横向和纵向的指定位置。它可以用作偏振分析仪以区分入射光的偏振状态。此外，根据光的旋转，我们的多功能金属元素可以充当凸透镜或轴锥。所展示的多维和多功能金属元素在自旋相关的纳米光子学中具有广泛的潜力，范围从光学成像，微/纳米物体操纵到光学传感。