Dai Hu, Li Detian, Yang Bin, Zhang Junqiang
Appl Opt. 2021 Jan 1;60(1):194-200. doi: 10.1364/AO.414783.
In this work, we present an accurate polarization reconstruction method based on the coherence demodulation technique, which is different from the previous windowing method operating in the optical path difference domain. The proposed method uses a signal multiplier and a low-pass filter to reconstruct Stokes parameters without performing any Fourier transform. Because this method does not require a Fourier transform, the Stokes reconstruction could be finished in the spectral domain. For calibrating the waveplate phase error, coherence demodulation allows for establishing an analytical model to describe the influence of waveplate imperfections on the polarization measurement process. The phase error will result in a channel shift and Fourier broadening, both of which cause serious errors during Stokes reconstruction. With the model, a method based on a linear polarizer was proposed for calibrating the phase deviation of waveplate. After that, the accurate reconstruction of polarization parameters could be achieved. An experiment was performed to check the ability of the proposed method. The experimental result showed that it has the same excellent performance of reconstructing Stokes parameters using the traditional windowing method. Finally, a series of simulations was carried out to verify the robustness of this method, which showed that the reconstruction technique is robust to misalignment and additional noise.
在这项工作中，我们提出了一种基于相干解调技术的精确偏振重建方法，该方法不同于先前在光程差域中操作的加窗方法。所提出的方法使用信号乘法器和低通滤波器来重建斯托克斯参数，而无需执行任何傅里叶变换。由于该方法不需要傅里叶变换，因此斯托克斯重建可以在频域中完成。为了校准波片相位误差，相干解调允许建立一个解析模型来描述波片不完善对偏振测量过程的影响。相位误差将导致通道偏移和傅里叶展宽，这两者在斯托克斯重建过程中都会引起严重误差。利用该模型，提出了一种基于线性偏振器的方法来校准波片的相位偏差。在此之后，可以实现偏振参数的精确重建。进行了一项实验来检验所提出方法的能力。实验结果表明，它具有与传统加窗方法相同的出色的斯托克斯参数重建性能。最后，进行了一系列模拟以验证该方法的鲁棒性，结果表明该重建技术对失准和附加噪声具有鲁棒性。
