Research on two-dimensional designer optical structures, or metasurfaces, has mainly focused on controlling the wavefronts of light propagating in free space. Here, we show that gradient metasurface structures consisting of phased arrays of plasmonic or dielectric nanoantennas can be used to control guided waves via strong optical scattering at subwavelength intervals. Based on this design principle, we experimentally demonstrate waveguide mode converters, polarization rotators and waveguide devices supporting asymmetric optical power transmission. We also demonstrate all-dielectric on-chip polarization rotators based on phased arrays of Mie resonators with negligible insertion losses. Our gradient metasurfaces can enable small-footprint, broadband and low-loss photonic integrated devices.

中文翻译：

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使用相梯度超表面控制波导模式的传播和耦合

二维设计器光学结构或超表面的研究主要集中在控制在自由空间中传播的光的波阵面。在这里，我们表明，由等离激元或介电纳米天线的相控阵组成的梯度超表面结构可用于通过亚波长间隔处的强光散射来控制导波。基于此设计原理，我们通过实验演示了支持非对称光功率传输的波导模式转换器，偏振旋转器和波导设备。我们还演示了基于Mie谐振器相控阵的全电介质片上偏振旋转器，其插入损耗可忽略不计。我们的梯度超表面可以实现占地面积小，宽带和低损耗的光子集成设备。