近红外超透镜的设计与制备

Design and fabrication of near-infrared metalens

  • 摘要: 超透镜是基于超表面的成像器件,能够精确调控光的相位、偏振、振幅,具有轻薄、易集成、平面化的优点。针对近红外成像器件的小型化、集成化发展趋势,基于非晶硅材料设计制备了近红外偏振不敏感超透镜。针对超透镜的基元结构选择问题,对比了采用8阶、6阶基元设计的超透镜聚焦效率;为提高加工容差和降低加工难度,采用了最大深宽比为6的8阶基元设计超透镜;针对超透镜仿真与加工之间跨度大的问题,利用化学气相沉积的方法生长了600 nm厚度的多晶硅,利用电子束刻蚀等工艺制备了超透镜样品。测试结果表明:超透镜形貌结构良好,聚集效率为65%。

     

    Abstract: Metalens is an imaging device based on metasurfaces, which can accurately regulate the phase, polarization, and amplitude of light. It has advantages of lightweight, easy-integration and planarizartion. For miniaturization and integration of near-infrared imaging devices, a near-infrared polarized insensitive metalens based on amorphous silicon was designed and fabricated. For selecting basic structures, the focusing efficiency of metalenses designed by 8-order and 6-order primitives were compared. To improve the processing tolerance and reduce the processing difficulty, the 8-order primitive was used to design metalens, and the maximum depth-width ratio was 6. For large-span between simulation and processing of metalens, the 600 nm-thick polysilicon by chemical vapor deposition was grew. The metalens was made by electron beam etching. The measured results show that the metalens has a good appearance and the focusing efficiency is 65%.

     

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