基于计算全息图的大口径长焦距离轴抛物面反射镜测量  

Measurement of Large Aperture Long Focus Off⁃Axis Paraboloid Mirror Based on Computer Generated Hologram

作　　者：胡晨[1,3] 魏朝阳 万嵩林[1] 江国昌 顾昊金 邵建达 Hu Chen;Wei Chaoyang;Wan Songlin;Jiang Guochang;Gu Haojin;Shao Jianda(Precision Optical Manufacturing and Testing Center,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;Key Laboratory for High Power Laser Material,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences Shanghai 201800,China;Center of Material Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院上海光学精密机械研究所精密光学制造与检测中心,上海201800 [2]中国科学院上海光学精密机械研究所高功率激光材料重点实验室,上海201800 [3]中国科学院大学材料科学与光电子工程中心,北京100049

出　　处：《中国激光》2024年第11期526-536,共11页Chinese Journal of Lasers

基　　金：国家自然科学基金青年基金(62205352);国家重点研发计划(2020YFA070304)。

摘　　要：随着激光脉冲宽度极限的不断突破以及峰值功率的不断提高,脉宽压缩光栅的尺寸需要进一步增大。但反射式曝光系统所需大口径长焦距离轴镜的高精度加工检测成为制约大口径光栅制作的难题。采用计算全息补偿检测不需要复杂的设计和装调,但同样会引入非回转对称和复杂的二维投影畸变。传统的畸变校正方法由于精度受限或计算复杂不利于工程应用。提出基于数值计算的畸变校正方法,该方法具有简单通用易于编程的优点。利用800 mm口径折反镜在直径为18 m光学平台上搭建了面形检测光路,通过系统误差标定去除以及畸变校正的方法实现了高精度面形测量,经磁流变迭代加工后,面形精度RMS可收敛至0.013λ(λ=632.8 nm),这为后续大口径反射式曝光系统的建立奠定了基础。Objective With the continuous development of laser pulse width limits and improvement of peak power,the size of the pulse compression grating(PCG)must be further increased.However,the high-precision manufacturing and testing of large aperture and long focal distance off-axis parabolic(OAP)mirrors required by reflective exposure systems,has presented a difficult challenge that restricts the manufacturing of large aperture gratings.The method based on computer generated holograms(CGH)does not require a complex design and setup,however,it introduces non-rotational symmetry and complex two-dimensional projection distortion.When correcting distortion,traditional marker point s and analytical methods have limited accuracy or complex calculations,which are not conducive to engineering applications.Therefore,this study proposes a distortion correction method based on numerical calculation,with the advantages of simplicity,versatility,and ease of programming.Based on the CGH test optical path,high-precision surface measurement can be achieved using system error calibration and distortion correction methods,laying the foundation for OAP mirror surface accuracy manufacturing and subsequent establishment of large aperture reflective exposure systems.Methods Initially,aΦ800 mm folding mirror is adopted to effectively shorten the optical path length,enabling development of a CGH measurement optical path on an 18 m vibration isolation air flotation optical table(Fig.2),and design a beam expansion system that matches the measurement aperture of the interferometer and CGH.Subsequently,the measurement errors introduced by the main optical elements in the optical path,excluding the interferometer,including CGH,beam expansion system,and fold mirror,are analyzed in detail,and the errors introduced are calibrated and removed.Thereafter,to ensure that the machining coordinate system matches the testing coordinate system,to achieve the precise positioning and convolution of the removal function and figure error,it is necessary to corre

关 键 词：离轴抛物面镜 计算全息图 误差标定 投影畸变校正 

分 类 号：O439[机械工程—光学工程]