基于Wollaston棱镜角剪切和Savart偏光镜横向剪切组合的可调光程的差分偏振干涉成像光谱系统，不仅可同时获取目标正交偏振分量的干涉图和二维空间图，而且可以通过调整Savart偏光镜的厚度，得到不同光程差下正交偏振分量的干涉图像。该系统的显著特点是正交图像的同时获取和光程的实时改变。描述了可调光程的差分偏振干涉成像光谱系统结构、理论原理，推导出了干涉强度表达式。详细分析了可调光程的Savart偏光镜(MSP)和可调光程的宽视场型Savart偏光镜(MWSP)的光程差及横向剪切量的变化范围。通过两种偏光镜之间的对比可得光程差差别甚微但MWSP剪切量较大，且变化量比MSP高50%。这为以后选择Savart偏光镜类型提供了重要依据。

The polarization-difference interference imaging spectrum system with adjustable optical path based on the combination of the angular shear of Wollaston prism and the lateral shear of Savart polariscope, can not only simultaneously obtain the two-dimensional space image and the interference image in the orthogonal polarization direction of the target, but also obtain the interference image in the orthogonal polarization direction under different optical path differences by adjusting the thickness of Savart polariscope. The features of the system are simultaneous acquisition of orthogonal images and real-time adjustment of optical path. The structure and theoretical principle of the polarization-difference interference imaging spectrum system with adjustable optical path are demonstrated. Expressions for the interference intensity are derived as well. The variation ranges of the optical path difference and the lateral displacement for the modulated Savart polariscope (MSP) and the modulated wide-field-of-view Savart polariscope (MWSP) are analyzed in detail. Through the contrast it is concluded that the optical path difference is little while the lateral displacement of MWSP is 50% higher than that of MSP. The results provide important evidence for the type selection of the Savart polariscope.