Abstract: In the imaging of living cells, the detection results of refractive index and thickness distribution have always been important parameters in the analysis of cell variation and morphology. In optical phase imaging, due to the coupling effect of RI and thickness of cells, the RI of cells cannot be directly measured, hence the decoupling method of RI and thickness of cells has always been a hot topic in this field. This article focuses on the subject of blood cells based on the free lable three-dimensional phase imaging information to establish dual wavelength phase shift equation, and analyse it by the three-dimensional phase imaging under dual wavelength phase information distribution and gradient distribution characteristics and obtain mathematical result of decoupling of the RI and thickness of homogeneous and nucleated heterogeneous samples by the dual wavelength phase distribution function. The RI and the thickness distribution of the outer cell and the inner core are obtained through the simulation experiments of the single medium model and the spherical outer cell kernel model. The error analysis shows that the method is highly accurate, which verifies the correctness of the method of this article. The proposed method can be used to decouple the RI and thickness distribution of red blood cells and five subgroups of white blood cells, which can provide a new method for the analysis of blood cell abnormality and cell morphology.
Key words: phase microscopic imaging; blood cell; refractive index; thickness distribution; decoupling method
（Acta Laser Biology Sinica, 2022, 31(2): 134-141）