基于相位传递函数的分块镜共相位倾斜误差检测  

Tip-Tilt Error Detection for Segments via Phase Transfer Function

作　　者：张璐 赵伟瑞[1,2] 赵跃进 刘娟[1,2] Zhang Lu;Zhao Weirui;Zhao Yuejin;Liu Juan(School of Optics and Photonics,Beijing Institute of Technology,Beijing 100081,China;Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology,Beijing 100081,China)

机构地区：[1]北京理工大学光电学院,北京100081 [2]精密光电测试仪器及技术北京市重点实验室,北京100081

出　　处：《光学学报》2024年第4期117-127,共11页Acta Optica Sinica

基　　金：国家自然科学基金(11874086)。

摘　　要：消除拼接主镜式望远镜的分块子镜间的共相位倾斜(tip-tilt)误差是有效提升集光能力、实现共相位成像的关键之一。提出了一种基于相位传递函数(PTF)的分块子镜的tip-tilt高精度检测方法。在分块镜的共轭面处设置具有离散孔结构的光阑,将其作为tip-tilt检测系统的入瞳,借助傅里叶分析,推导建立了误差检测系统的PTF与tip-tilt的函数关系,通过对探测得到的点扩散函数进行傅里叶分析,得到PTF,依据建立的函数关系即可实现tip-tilt的高精度检测。对所提方法进行了仿真分析和实验验证,检测精度的均方根(RMS)值为2.99×10^(-3)λ(λ为波长)。所提方法结构简单,只需要设置一个具有离散孔结构的光阑,可用于拼接式主镜、稀疏孔径系统的共相位tip-tilt误差检测。Objective In order to observe more distant and fainter objects with a better resolution and signal-to-noise ratio,larger primary mirror telescopes are required to improve the diffraction limit and increase the collected light energy.This leads to problems of manufacture,testing,transportation,and launch for monolithic primary mirrors.At present,it is hard to build a monolithic primary mirror with a diameter of 8 m or larger.The segmented primary mirror is thus adopted to address these issues.However,tip-tilt errors between segments must be eliminated to meet the requirements of the lightcollecting capacity and resolution.The existing tip-tilt error detection approaches mainly include the centroid detection method,phase retrieval/phase diversity(PR/PD)method,Shack-Hartmann phase sensing method,and other methods based on interferometry.In tip-tilt error detection,the centroid detection method is usually used in the coarse stages,and the PR/PD is used to eliminate the uncertainty of the centroid detection method in the fine stages.The Shack-Hartmann phase sensing method is separately used in coarse and fine stages,which also involve special-purpose hardware,complex structure,and unstable factors.Methods In this paper,a novel method,for detecting tip-tilt errors in a large capture range with a better accuracy via phase transfer function(PTF),is proposed.A mask with a sparse subpupil configuration is set on the segments'conjugate plane and serves as the entrance pupil of the tip-tilt error detection system.Then,the optical transfer function(OTF)with separated sidelobes can be obtained by the Fourier transform of the point spread function(PSF)recorded in the chargecoupled device(CCD)of the detection system,which makes it possible to separate the information of tip-tilt errors overlapped in the PSF.By analyzing the OTF sidelobes,the relationship between the phase distribution gradient of the OTF sidelobes and tip-tilt can be derived and used to extract the tip-tilt error without the measurement uncertainty of the centro

关 键 词：傅里叶光学 相位传递函数 分块镜 倾斜误差 离散孔光阑 傅里叶变换 

分 类 号：O439[机械工程—光学工程]