A broadband achromatic polarization-insensitive metalens consisting of anisotropic nanostructures
A broadband achromatic polarization-insensitive metalens consisting of anisotropic nanostructures
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DOI：
10.1038/s41467-019-08305-y
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发表时间：
2019-01-21
影响因子：
16.6
通讯作者：
Capasso, Federico
中科院分区：
文献类型：
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作者：
Chen, Wei Ting;Zhu, Alexander Y.;Capasso, Federico
由于对紧凑型和可穿戴光学设备的需求不断增长，超表面引起了广泛的关注。对于许多应用来说，偏振不敏感的超表面是非常理想的，并且似乎将其组成元素的选择限制为各向同性纳米结构。这极大地限制了设计中可用的几何参数的数量。在这里，我们展示了一种使用各向异性纳米鳍的偏振不敏感超透镜，它可以对输出光的色散和相位提供额外的控制。因此，我们可以使超透镜在波长 lambda = 460 nm 至 700 nm 的几乎整个可见光谱范围内消色差且对偏振不敏感，同时保持衍射极限性能。超透镜仅由单层 TiO2 纳米鳍组成，数值孔径为 0.2，直径为 26.4 μm。我们的偏振不敏感设计的通用性使其可以在大量其他超表面设备中实现，其应用范围从成像到虚拟/增强现实。
Metasurfaces have attracted widespread attention due to an increasing demand of compact and wearable optical devices. For many applications, polarization-insensitive metasurfaces are highly desirable, and appear to limit the choice of their constituent elements to isotropic nanostructures. This greatly restricts the number of geometric parameters available in design. Here, we demonstrate a polarization-insensitive metalens using otherwise anisotropic nanofins which offer additional control over the dispersion and phase of the output light. As a result, we can render a metalens achromatic and polarization-insensitive across nearly the entire visible spectrum from wavelength lambda = 460 nm to 700 nm, while maintaining diffraction-limited performance. The metalens is comprised of just a single layer of TiO2 nanofins and has a numerical aperture of 0.2 with a diameter of 26.4 mu m. The generality of our polarization-insensitive design allows it to be implemented in a plethora of other metasurface devices with applications ranging from imaging to virtual/augmented reality.