Metalenses offer a unique platform to focus light by manipulating the properties of an incoming light wavefront. It is still a challenge to create an achromatic polarization-independent metalens, because of the complexity of satisfying the phase profile and group delay at the same time. In this paper, we propose an achromatic and polarization-independent metalens based on four-fold symmetric LiNbO₃ meta-unit elements which works well in the visible band from 400 to 760 nm. The numerical aperture of our metalens is 0.125, and the transmission efficiency is over 90%, the average focusing efficiency is nearly 71%.

中文翻译：

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基于铌酸锂绝缘体的宽带消色差元透镜

Metalenses 提供了一个独特的平台，通过操纵入射光波前的特性来聚焦光。由于同时满足相位分布和群延迟的复杂性，创建消色差偏振无关元透镜仍然是一个挑战。在本文中，我们提出了一种基于四重对称 LiNbO ₃元单元元件的消色差和偏振无关元透镜，该元透镜在400 到 760 nm 的可见波段工作良好。我们的超透镜数值孔径为0.125，传输效率超过90%，平均聚焦效率接近71%。