傅立叶变换型线偏振干涉成像系统分析与设计

Analysis and design of Fourier transform polarization interference imaging system

为满足中波红外高空间分辨率偏振干涉测量需求,本文提出一种基于微型静态干涉原理的中波红外线偏振干涉成像系统。该系统不含狭缝,具有信息量多,光通量大等优点。介绍了线偏振干涉成像系统的工作原理,采用近轴光学理论计算了初始结构参数,进行了系统优化设计。分析了入射光分别为完全非偏振光和线偏振光时系统的透过率,给出了系统所能探测的最小辐射强度。为了降低探测器强度的随机波动对偏振测量的影响,采用等权重方差优化了系统的偏振测量矩阵,并通过数值仿真验证了方法的正确性。最后,分析了偏振片的旋转误差对偏振测量的影响,给出了偏振探测精度为2%时的偏振片旋转公差容限。设计结果表明:傅立叶变换型线偏振干涉成像系统成像质量良好,在探测器的特征频率17 lp/mm处,各视场的调制传递函数值均大于0.6,满足系统的使用需求。

In order to achieve high spatial resolution polarization interferometry in the infrared wave band,a novel polarization interference imaging system based on micro-static interference systems is proposed in this paper.The system does not contain slits and has the advantage of having a large luminous flux.This paper introduces the principles of a linear polarization interference imaging system,calculates its initial structure parameters by using the Paraxial optics theory and optimizes the system's design.When the incident light is completely non-polarized and polarized,the transmission rate of the system is analyzed and the minimum weak radiation detected by the system is obtained.In order to further improve the system's performance and reduce the effect of random fluctuations in detector intensity on polarization measurements,the polarization measurement matrix of the system is optimized by using equal weight variance and the correctness of the method is verified by numerical simulation.Finally,the influence of the Polarizer's rotation error on the polarization measurement is analyzed,and the tolerance of polarizer is given in order to satisfy the polarization detection accuracy of 2%.The design results show that the imaging quality of the Fourier transform line polarization interference imaging system is good and that the modulation transfer function value of each field is greater than 0.6 in the characteristic frequency 17 lp/mm of the detector,which meets the usage requirements of the system.