大口径硅基空间红外透镜的高精度加工与检测（特邀）

随着红外技术的不断发展，空间大口径红外光学元件的需求日益增长，其各项制造指标也逐渐接近可见光级光学元件的制造要求，由此对新型空间红外光学元件的加工和检测技术均提出了更高的挑战。针对大口径的高陡度超薄硅基红外透镜，提出了以超声铣磨-机器人研抛-离子束精抛为工艺链路的加工方案，改善了传统红外工艺路线存在的低效率、表面高频误差等问题。针对凸非球面轮廓检测中支撑引起的测试误差，在粗抛和精抛阶段分别采用了柔性缓冲支撑与三点强迫位移支撑方法，有效解决了大口径高陡度超薄透镜测试中的支撑变形问题。经过理论仿真与实验验证，证明该测试方法具有较好的一致性。通过改进的轮廓检测方法，实现了轮廓测试中支撑误差的准确分离，有效提升了加工的极限精度。最终大口径红外透镜凸非球面加工精度达RMS λ/50 （λ=632.8 nm），满足设计指标要求。

High precision manufacturing and testing of large aperture silicon-based space infrared lens (invited)

With the development of infrared technology, the demand for large aperture space infrared optics is increasing. Their manufacturing indexes are approaching the manufacturing requirements of visible optics gradually, which poses a higher challenge to the processing and testing technology of new infrared optics. A processing scheme of ultrasonic milling, robot griding and ion beam polishing was proposed for the manufacturing of large diameter ultra-thin silicon-based infrared lens with high gradient. This method overcame the defects of low efficiency and high frequency surface error caused by single process. In order to avoid the testing error caused by supporting force in contour testing of the aspherical convex side, flexible buffer supporting and three-point forced displacement supporting were applied in rough and fine polishing phases respectively, which effectively solved the supporting deformation problem in the testing of large aperture and high gradient ultra-thin lens. Through theoretical simulation and experimental verification, it was proved that the testing method had good consistency. An improved contour detection method was adopted to achieve accurate separation of supporting error in contour testing, and has effectively improved the limit accuracy of manufacturing. Finally, the machining accuracy of convex aspheric surface with large diameter mm infrared lens reached RMS λ/50 (λ=632.8 nm), which satisfied the design requirements.