基于数字全息及复用技术的全场偏振态测试方法

提出了一种在数字全息记录系统中利用偏振和角分复用技术对光场进行偏振态检测的方法. 将全息系统中的一束参考光分为偏振方向相互正交、初相位相同的两束光, 并分别与物光相同偏振方向的两个分量干涉, 形成两幅子全息图, 同时记录在一帧画面中. 为了分开记录到的物光两个分量, 系统中利用了角分复用技术, 即在两束参考光中引入不同载频, 使物光两分量的频谱位于全息图频谱面的不同区域. 通过滤波、逆傅里叶变换和衍射计算, 获取距离全息图不同位置处物光两正交分量复振幅信息. 利用复振幅信息, 可以构建被测物光的斯托克斯参量和琼斯矢量, 从而表征物光的偏振态. 实验中, 通过对一束椭圆偏振光进行偏振态测量以及对该光束在不同空间位置处的偏振态进行表征, 表明该方法可以实现光束偏振态全场测试, 并且具有较高的可靠性. 关键词： 数字全息 偏振态 琼斯矢量 斯托克斯参量

Full-field detection of polarization state based on multiplexing digital holography

Based on digital holography recording system, it is proposed to use both polarization and angular multiplexing techniques to detect a polarization state. Reference beam is divided into two beams with orthogonal polarization directions and equal initial phases. And the beams interfere with the two orthogonal components of object wave respectively, which generates two holograms recorded in one frame. The use of angular multiplexing separates the two orthogonal components of object wave in the Fourier domain by respectively introducing carriers towards different directions. By numerical filtering, inverse Fourier transform and then diffraction calculation, complex amplitude of object wave can be obtained at different distances to the holograms. With the obtained complex amplitude, it is possible to work out both the Stokes parameters and Jones vector, which describe the polarization state of the object wave. The measuring of elliptical polarization state and the characterizing of polarization states at different locations on axis prove the validity of this real-time full-field detection method.
Keywords： digital holography state of polarization Jones vector Stokes parameters