Liu Xin, Li Min, Li Bincheng, Fan Bin
Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China.
School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China.
Polymers (Basel). 2022 Jul 28;14(15):3056. doi: 10.3390/polym14153056.
The membrane-Fresnel diffractive lens (M-FDL) has great potential in the field of high-resolution and lightweight imaging in orbit. However, the M-FDL with high-optical quality and high-thermal stability cannot be fabricated to a standard by the existing processing methods. In this paper, we propose a method for fabricating an M-FDL composed of three steps: the improved repeated spin-coating of the polyimide (PI) membrane, the secondary mucosal method of silica-framed membrane mirror, and the high-precision fabrication of a multi-level microstructure on a flexible, ultrathin membrane substrate. The results show that the root mean square (RMS) of the wave-front error for M-FDL obtained by the above method is 1/28λ (F# = 8.7 at 632.8 nm) with an 80 mm clear aperture, the average diffraction efficiency is more than 70%, the silica-framed membrane mirror possesses approximately 40 times the overall thermal stability of the traditional metal-framed mirror, and the weight is less than 40 g. The measurement results indicate that the M-FDL has high-optical quality and high-thermal stability and can satisfy the imaging requirements.
膜菲涅耳衍射透镜（M-FDL）在轨道高分辨率和轻量化成像领域具有巨大潜力。然而，现有的加工方法无法将具有高光学质量和高热稳定性的M-FDL加工到标准要求。本文提出一种制造M-FDL的方法，该方法包括三个步骤：改进的聚酰亚胺（PI）膜重复旋涂、二氧化硅框架膜镜的二次黏膜法以及在柔性超薄膜基板上高精度制造多级微结构。结果表明，通过上述方法获得的M-FDL的波前误差均方根（RMS）为1/28λ（632.8nm波长下F# = 8.7），有效孔径为80mm，平均衍射效率超过70%，二氧化硅框架膜镜的整体热稳定性约为传统金属框架镜的40倍，重量小于40g。测量结果表明，M-FDL具有高光学质量和高热稳定性，能够满足成像要求。
