基于超消色差1/4波片和AOTF的高光谱全偏振成像技术

Technology of hyperspectral full polarization imaging based on superachromatic 1/4 wave plate and acousto-optic tunable filter

  • 摘要: 针对环境温度、电压、入射角等因素变化对基于声光可调谐滤波器(Acousto-optic tunable filter,AOTF)和液晶可变延迟器(Liquid crystal variable retarder,LCVR)的光谱偏振成像测量精度影响大,且整个系统实现复杂等缺点;考虑到超消色差波片对温度和波长依赖小,结合AOTF高光谱成像的优点,提出了基于超消色差1/4波片和AOTF的高光谱全偏振成像新方法。详细分析了该方法的工作原理,并结合可购买到的最好超消色差1/4波片中相位延迟和快轴随波长的微小波动,进而分析了该波动对偏振测量的影响,并针对这些影响研究了修正策略。搭建了原理样机,对450~950 nm波段进行了偏振测量,修正后偏振度测量误差 1%,对偏振方向的测量偏差 1.8,以633 nm为例,对其全Stokes参量图像进行了具体原理及修正测量验证实验,结果表明,该新技术原理正确,修正策略可行。该研究可为复杂条件下高精度、高光谱全偏振成像技术提供新的理论和实现方案。

     

    Abstract: The measurement accuracy of spectropolarimetric imaging is severely affected by ambient temperature, voltage, and incident angle based on acousto-optic tunable filter(AOTF) and liquid crystal variable retarder(LCVR). The spectropolarimetric imaging system is more complex. However, the superachromatic wave plate has the advantage that the retardation varies very little with temperature and wavelength. According to it, a new method of full polarization hyperspectral imaging based on superachromatic wave plate and acousto-optic tunable filter was proposed. The working principle of the method was analyzed in detail. According to the slight fluctuation of retardation and the fast axis of the superachromatic 1/4 wave plate, the effect of this fluctuation on the polarization measurement was analyzed in detail. For these errors, a correction strategy was proposed. The specific principle of all the Stokes parameters images and the modified measurement verification experiment were performed for 633 nm waveband. The experiment result shows that the measurement error of the polarization degree of the system is less than 1% in the band of 450-950 nm, and the measurement deviation of the polarization orientation is less than 1.8. The experimental results show that the new technology principle is correct and the correcting strategy is feasible. This research can provide new theory and implementation scheme for high-precision, high-resolution, full-polarization imaging technology under complex conditions.

     

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