双孔点衍射干涉成像系统波像差检测技术研究  

Dual-Hole Point Diffraction Interferometer for Measuring the Wavefront Aberration of an Imaging System

作　　者：冯鹏[1,2] 唐锋 王向朝[1,2] 卢云君 徐静浩[1] 郭福东 张国先[1] Feng Peng;Tang Feng;Wang Xiangzhao;Lu Yunjun;Xu Jinghao;Guo Fudong;Zhang Guoxian(Laboratory of Information Optics and Opto-Electronic Technology,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;Center of Materials 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信息光学与光电技术实验室,上海201800 [2]中国科学院大学材料与光电研究中心,北京100049

出　　处：《中国激光》2021年第9期105-112,共8页Chinese Journal of Lasers

摘　　要：提出了一种用于测量高精度成像系统的双孔点衍射干涉仪,具有高光场均匀性、高可测量数值孔径、准共光路、相移元件在系统成像光路以外的优点。设计了两种测量模式,点衍射测量模式和系统误差测量模式,其中系统误差模式用于标定干涉仪的系统误差。分别搭建了双孔点衍射干涉和双光纤点衍射干涉的实验装置,完成了对设计波像差小于0.045λ RMS,5×透射式投影物镜的检测实验。实验结果表明,与双光纤点衍射干涉仪对比,双孔点衍射的波像差测量相对误差为0.07 nm RMS,且干涉图具有更加良好的光强均匀性。验证了本文检测技术的有效性。Objective Wavefront aberration describes the properties of a small-aberration imaging optical system.In a high-quality microscope objective lens and space telescope,the wavefront errors should be withinλ/14 RMS(whereλis the operational wavelength and RMS is the root mean square value).To meet required wavefront quality of the optical systems for extreme ultraviolet lithography,the error must be less than 0.45 nm RMS.Therefore,wavefront measurements are highly demanded.At present,wavefronts are typically measured by Hartmann sensors,Fizeau interferometers,Twyman-Green interferometers,shearing interferometry,or point-diffraction interferometry.The Shark-Hartmann sensor covers a large measurement range and can quickly measure the wavefront,but with lower resolution than interferometry.The Fizeau and Twyman-Green interferometers cannot measure to higher accuracy than their standard lenses,and cannot be installed in systems with limited space.In the present study,we report a phase-shifting point-diffraction interferometer with several advantages:high optical field uniformity,high measurable numerical aperture,and a quasi-common optical path.The optical signals are transmitted through single-mode fibers that improve the flexibility of the interferometer system.Our results are anticipated to assist wavefront-aberration detection in high-precision photolithographic projection lenses.Methods We developed a dual-hole point diffraction interferometer(DHPDI)based on a dual-fiber optical path.First,we designed the measuring principle of the interferometer.The interferometer uses a diode-pumped solid-state laser with multi-longitudinal modes.The laser operating wavelength is 532 nm and the coherence length is several centimeters.The two laser beams form a quasi-common optical path interferometer structure.The intensities of the beams are controlled by interference arms connected with adjustable attenuators,one of which is connected to a phase shifter.The two single-mode optical fibers of the object surface output two beams o

关 键 词：测量 点衍射 针孔点衍射 波像差检测 干涉测量 

分 类 号：O436.1[机械工程—光学工程]