基于偏振分束的磁光成像技术研究

Research on magneto-optic imaging based on polarization beam splitter

针对现有磁光成像技术的测量结果难以量化且受光源波动影响较大的问题,提出了一种基于偏振分束的磁光成像新方法。根据偏振光的琼斯矢量描述方法推导出偏振分束法测量旋光角度的模型,并由此模型分析得出,从旋光物质出射的偏振光经偏振分束装置后输出的平行分量和垂直分量进行"差除和"的结果与入射光强无关,只和旋光角度值相关;由此原理,设计了基于CCD的检测平台,对旋光角度场进行了测量实验,又采用归一化互相关和"差除和"算法对测量图像进行了处理;最后,进行了基于该方法的磁光成像应用实验研究。实验结果表明,与传统磁场成像方法相比,该方法操作简单,结果易于量化,不受光强波动影响,误差降低约3倍,且稳定性较好。

Aiming at the problem that the result of MOI is difficult to be quantified and greatly affected by the fluctuation of light, a new MOI method based on polarization beam splitter is proposed. Firstly, the measurement model for rotation angles based on polarization beam splitter is build using Jones vector. According to this model, if the light is split into S light and P light, the result of their intensity processing is only related to the rotation angles and independent of the light fluctuation. A test platform based on CCD was designed and implemented to measure the distribution of rotation angles. Then the images acquired with the CCD were processed based on normalized cross correlation. Lastly, MOI imaging experiment studies using this method show that compared with traditional methods, this method is simple, and the results are easy to quantify; the results are not affected by the instability of the light, the errors are reduced by roughly 3 times and the results are more stable.