提出了一种基于萨伐尔(Savart)偏光镜双折射晶体进行光谱分光的显微偏振干涉成像光谱仪的创新性原理和方案；从几何光学的角度推导了显微偏振干涉成像光谱仪景深的理论计算公式；给出了景深与光谱分辨力的变化关系，证明了景深的存在使系统光谱分辨力不再唯一确定，而是在一定范围内连续变化；通过计算机模拟分析了景深对系统分辨力的影响。该研究对实现快速实时测量，减少景深对光谱分辨力的影响以及新型偏振干涉成像光谱仪的研究、研制和工程化提供了重要的理论依据和实践指导。

A scheme of microscope polarization interference imaging spectrometer (MPIIS) based on a Savart polariscope and its basic principles are introduced, and the relative expression of depth of field of MPIIS is derived with the geometrical-optics method. The relationship between the depth of field and the spectral resolution is given. It proves that the existence of the depth of field renders the spectral resolution value unfixed, but changing continuously within a certain range. The influence of depth of field on resolution value of a MPIIS is analyzed through computer simulation. All of this provide important theoretical bases and practical guidances for realizing real-time measurement, decreasing influence of depth of field on spectral resolution, and the study, design and engineering of novel polarization interference imaging spectrometers.