菲佐光干涉望远镜实现高分辨率成像的关键是各子孔径之间相位平移误差的共相检测.基于物理光学基本原理,论证了两个子孔径在单色光条件下其远场干涉条纹峰值偏移量与其相位平移误差之间的近似线性关系,提出了一个波长范围内的平移误差检测方法;进而提出了基于光栅色散干涉条纹的共相检测方法,并对其可行性、检测精度和检测范围进行了理论分析与仿真实验.结果表明,该方法在原理上可以实现对两孔径的相位平移误差进行直接检测,50μm范围内平移误差的检测精度优于20 nm,解决了既有方法可能存在的2π模糊性及无法判断平移误差正负的问题.该方法为共相检测技术的进一步研究提供了新的途径和参考.
For the Fizeau optical interferometric telescope system, the co-phasing detection of piston errors between sub- apertures plays an important role in realizing the high resolution of system. In this paper, the relationship between piston error and the main peak displacement of monochromatic interferogram of two sub-aperture system is analyzed based on physical principles, then the piston error detecting method is developed and clarified based on their linear relationship in the range of one wavelength. Furthermore, an innovative co-phasing detecting method based on grating dispersed interferogram with bandwidth light source is proposed, and its feasibility, detecting precision and dynamic range are analyzed in theory and studied in simulation. The results prove that with this method, the piston error between the two sub-apertures of the system can be soundly detected and its measuring error is less than 20 nm while the piston error is not more than 50 μm. In addition, the novel method solves the problems of 2~ ambiguity and direction determination that might exist within some other detecting methods. Besides its millimeter level dynamic range, this new co-phasing detecting method provides a new way and an effective reference for in-depth research of co-phasing detecting techniques.